First Step To Repair Laptop Motherboard v1 [PDF]

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Copyright All Rights Reserved Warning! All rights reserved. No part of this E-book may be reproduced or transmitted in any form, by any mean (electronic, photocopying, recording, or otherwise) without the prior written permission of the LaptopRepairSecrets, except in the case of brief quotations embodied in critical reviews and certain other non commercial uses permitted by copyright. If you find this content to be valuable and want to share it, please direct people to purchase a copy from www.LaptopRepairSecrets.com a lot of hard work, time, and expertise went into creating this resource. Your support is greatly appreciated! Any trademarks, service marks, product names, or named features in this E-book are assumed to be the property of their respective owners and are used only for reference. There is no implied endorsement if the author uses one of these terms. Much of this publication is based on personal experience and anecdotal evidence. Although the author has made every reasonable attempt to achieve complete accuracy of the content in this E-book, he assumes no responsibility for errors or omissions. Limit of Liability / Disclaimer of Warranty The author and publisher of this E-book and the accompanying materials have used their best efforts in preparing this program. The authors and publisher make no representation or warranties with respect to the accuracy, applicability, fitness, or completeness of the contents of this program. They disclaim any warranties (expressed or implied), merchantability, or fitness for any particular purpose. The reader is expressly warned to consider and adapt all safety precautions that might be indicated by the activities here in and to avoid all potential hazards. By following the instructions contained herein, the reader willingly assumes all risks in connection with such instructions. The authors and publisher shall in no event be held liable for any loss or other damages, including but not limited to special, incidental, consequential, or other damages. As always, the advice of a competent legal, tax, accounting or other professional should be sought.

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Table of Contents Introduction ----------------------------------------------------------------- 12 Important notice for your Safety -------------------------------------- 13 Part 1 Tools and Testing Equipments Types and Functions Repair Tools to Troubleshoot Laptop---------------------------------15 Cleaning Tools---------------------------------------------------------------16 Screwdrivers Tools---------------------------------------------------------16 Soldering Tools--------------------------------------------------------------17 Bios I/O KBC Programmers ----------------------------------------------20 ESD Safe Tools---------------------------------------------------------------21 Inspection Tools-------------------------------------------------------------22 Electronic Measuring Tools ----------------------------------------------23 Laptop Battery Tester -----------------------------------------------------24 Gripping Tools ---------------------------------------------------------------25 Other Tools -------------------------------------------------------------------25 Part 2 Laptop Parts Tour Basic Laptop Hardware Tour--------------------------------------------28 Laptop Case------------------------------------------------------------------28 Motherboard----------------------------------------------------------------29 RAM Memory Cover Door-----------------------------------------------29 DVD/CD-RW Driver--------------------------------------------------------30 Battery ------------------------------------------------------------------------31 Power Adapter--------------------------------------------------------------32

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KeyBoard----------------------------------------------------------------------33 Laptop Memory-------------------------------------------------------------33 Hard Driver-------------------------------------------------------------------36 Touchpad/Trackpad--------------------------------------------------------38 Mouse Buttons --------------------------------------------------------------49 Laptop Screen----------------------------------------------------------------49 Screen Inverter---------------------------------------------------------------41 Screen Cable-------------------------------------------------------------------41 Web Camera-------------------------------------------------------------------42 CPU Fan-------------------------------------------------------------------------42 CMOS Battery-----------------------------------------------------------------43 CPU Central Processing Unit----------------------------------------------44 LID Close Switch -------------------------------------------------------------44 Front Bezel--------------------------------------------------------------------45 Cover-Lid with Wi-Fi Antenna--------------------------------------------45 Wi-Fi Cards--------------------------------------------------------------------46 Hinges Rails-------------------------------------------------------------------46 Hinge Covers------------------------------------------------------------------47 SD Card Reader---------------------------------------------------------------47 Power Button Board--------------------------------------------------------48 Other Hardware Parts------------------------------------------------------48 Motherboard Overview----------------------------------------------------49 Top 10 Youtube Channels Tech Laptop Disassembly---------------52

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Part 3 Basic Electronics What is Electricity?----------- ----------------------------------------------54 What is an Electron?---------------------------------- ---------------------54 Voltage Pushes Electrons--------------------------------------------------56 Current Flows-----------------------------------------------------------------56 Resisstance Reduces Current---------------------------------------------57 Types of Current-------------------------------------------------------------58 How do we Measure Electricity?----------------------------------------59 Effective Resisstance--------------------------------------------------------61 Binary Number system-----------------------------------------------------64 Bits and Bytes-----------------------------------------------------------------65 Logical---------------------------------------------------------------------------66 Logic Gates---------------------------------------------------------------------67 AND Gates Check for Tow True Input-----------------------------------68 OR Gates Check for One True Input-------------------------------------68 Not Gates Flip Inputs--------------------------------------------------------69 A Bigger AND Gates----------------------------------------------------------69 Part 4 Electronics Components The Main Electronic Components in Laptop Motherboard-------72 Capacitor-----------------------------------------------------------------------73 Capacitors Testing------------------------------------------------------------83 Resistor--------------------------------------------------------------------------86 Resistor Testing---------------------------------------------------------------91

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Inductor–Coil------------------------------------------------------------------98 Inductor Testing-------------------------------------------------------------100 Fuse-----------------------------------------------------------------------------101 Fuse Testing------------------------------------------------------------------102 Diode---------------------------------------------------------------------------103 Testing Diode----------------------------------------------------------------106 Zener Diode------------------------------------------------------------------107 Testing Zener Diode------------------------------------------------------- 108 Transformer------------------------------------------------------------------109 Crystal Oscillator------------------------------------------------------------110 Transistor---------------------------------------------------------------------112 Intergrated Circuit (IC)-----------------------------------------------------128 The most important integrated circuits are in laptop motherboard------130

EEPROM-----------------------------------------------------------------------131 Super I/O----------------------------------------------------------------------135 Clock Generator-------------------------------------------------------------136 Voltage Regulator----------------------------------------------------------137 PWM Controller-------------------------------------------------------------140 Microprocessor--------------------------------------------------------------142 Part 5 Identifying of Common Components of the Laptop Motherboard Capacitors (C)----------------------------------------------------------------144 Inductor – Coil (L)-----------------------------------------------------------146 Fuse (F)------------------------------------------------------------------------148

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Diode (D)----------------------------------------------------------------------149 Zener Diode (ZD or PD)----------------------------------------------------149 LED------------------------------------------------------------------------------150 Crystal (X or Y)---------------------------------------------------------------150 Resistors (R)------------------------------------------------------------------151 Mosfet (Q)--------------------------------------------------------------------152 Transistor (Q)----------------------------------------------------------------153 Bios IC--------------------------------------------------------------------------153 FAN Connector--------------------------------------------------------------153 Bios-----------------------------------------------------------------------------154 Part6 Documents Related to the Laptop Motherboard User Manual-----------------------------------------------------------------156 Service Manual--------------------------------------------------------------156 Schematic Diagram---------------------------------------------------------157 Block diagram--------------------------------------------------------------- 157 Datasheet---------------------------------------------------------------------158 Part 7 How to Read Datasheet How to Read DataSheet?-------------------------------------------------160 Pin Configuration-----------------------------------------------------------161 Part 8 Motherboard Part Numbers What is laptop ODM?------------------------------------------------------164 How to get the schematic diagram?-----------------------------------165

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Part 9 How to Read Laptop Schematic? What’s the schematic diagram?----------------------------------------169 Important Part Schematic Diagram------------------------------------169 Understanding Basic of Schematic-------------------------------------172 Schematic Path and Connection Between Circuits----------------173 Information-------------------------------------------------------------------177 Finding signs-----------------------------------------------------------------179 Related Search---------------------------------------------------------------180 How to deal with schematics that don't have the power sequence------185

Part 10 Signal Explanation of common signal name---------------------------------190 Signals-------------------------------------------------------------------------190 The Power good signal----------------------------------------------------190 The open signal-------------------------------------------------------------192 Reset Signal------------------------------------------------------------------193 +5VALW +3VALW signal--------------------------------------------------194 PWR_S5_EN------------------------------------------------------------------194 Clock signal-------------------------------------------------------------------196 Chip Select Signal-----------------------------------------------------------196 Part 11 The Architecture of the Laptop Motherboard Power supply and signal--------------------------------------------------199 The AMD single bridge architecture (A70)---------------------------200 The Nvidia architecture double bridge (C51M)---------------------201

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High-level and low-level signals----------------------------------------203 The architecture of Nvidia single bridge (MCP67)-----------------206 Part 12 The Basic Knowledge You Must Know Before Starting to Repair Laptop What is a short circuit?----------------------------------------------------216 Finding a short---------------------------------------------------------------217 What is a voltage divider?------------------------------------------------218 What are System Power STATES?--------------------------------------220 What is a DC to DC boost circuit?--------------------------------------221 What is a feedback?-------------------------------------------------------222 Diagnostic method for laptop power supply circuit failure-----223 Laptop motherboard power supply-----------------------------------224 Protection isolation circuit----------------------------------------------224 Charging control circuit--------------------------------------------------225 Standby circuit--------------------------------------------------------------229 System power supply circuit--------------------------------------------229 Analysis Linear Regulated Power Supply Type Standby Circuit------------230

Switching power supply type standby circuit-----------------------231 CPU circuit--------------------------------------------------------------------235 CPU core power supply circuit------------------------------------------238 Memory circuit--------------------------------------------------------------240 B+ Supply with Hp Adaptor----------------------------------------------243 Enable B+ supply through adaptor-------------------------------------244 Disable supply through battery-----------------------------------------244 Under voltage and Overvoltage Detection--------------------------245

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LED indicator Enable-------------------------------------------------------246 COMPAQ CQ40 Standby Supply Description------------------------246 Over Voltage and Under Voltage Protection------------------------249 HP CQ40 Battery Charging Discription--------------------------------249 Adaptor detection for charging IC and Enable charging----------252 Adaptor current sensing and input------------------------------------254 Battery Full Charge detection-------------------------------------------254 Why need to Convert or Bypass the DIS Graphic to UMA in Laptop?----255

Part 13 Laptop motherboard Repair Flowchart Power off Problem---------------------------------------------------------260 Dead Laptop-----------------------------------------------------------------261 Power on but no display--------------------------------------------------262 Display ok but backlight no work---------------------------------------263 Battery Charging Problem------------------------------------------------264 Lining Display Problem----------------------------------------------------265 USB Problem-----------------------------------------------------------------265 Sound Problem--------------------------------------------------------------266 Part 14 Dictionary for Technicians Name Components Code Table-----------------------------------------268 The motherboard common signal definition------------------------270 SIO pin description---------------------------------------------------------273 Power Chips Code Number-----------------------------------------------247 Conclusion--------------------------------------------------------------------275

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Introduction: Welcome to this training on laptop motherboard repair and maintenance, Laptop technology has become one of the fastest growing technologies in the world, today people use Laptop to stay in touch with friends and family. This widespread ownership and use of laptop have created a need for professionals who can repair and service Laptop, this E-Book has been developed to address that need,the E-Book targets people who would like to start and run a laptop repair and servicing business, By the end of this E-book you should be able to diagnose the problem and service and repair a laptop motherboard with the help of proper tools and instruments. This E-Book is provided through distance learning and we trust that you will find the material useful both for studying and as future reference, please take the time to read this E-book in its entirety, then re-read it again to ensure you get a clear understanding of all its content. We welcome your feedback on any issue relating to this E-Book and wish you all the best. Happy Learning!

www.LaptopRepairSecrets.com

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Important notice for your sefety Please remove covers and other parts in a safe place, away from all personnel, while you are servicing the laptop motherboard. Keep your tool case away from walk areas so that other people will not trip over it. Do not wear jewelry, chains, metal-frame eye glasses, or metal fasteners for your clothing metal objects are good electrical conductors. Wear safety glasses when you are hammering, drilling, soldering, cutting wire, attaching springs, using solvents, or working in any other conditions that may be hazardous to your eyes. After service, reinstall all safety shields, guards, labels and ground wires. Replace any safety device that is worn or defective. Use only one hand when working with powered-on electrical motherboard and keep the other hand in your pocket or behind your back. Do not use worn or broken tools. Before the laptop is powered on after replacement any part, make sure all screws and other small parts are in place and are not let loose inside the laptop. Verify this by shaking the laptop and listening for rattling sounds. Metallic parts or metal flakes can cause electrical shorts. Some standby batteries contain a small amount of nickel and cadmium. Do not disassemble a standby battery, recharge it, throw it into fire or water or short circuit it. If the LCD breaks and the fluid from inside the LCD gets into your eyes or on your hands, immediately wash the affected areas with water at least for 15 minutes.

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Part 1 Tools and Testing Equipment Types and Functions

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Repair Tools to Troubleshoot Laptop To troubleshoot and repair laptop systems properly, you need a few basic tools. If you intend to troubleshoot and repair systems professionally, you may want to purchase many more specialized tools as well, these advanced tools enable you to more accurately diagnose problems and make jobs easier and faster, here are the basic tools that should be in every troubleshooter’s toolbox…!!! The basic tools you need to work on a laptop are shown here

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Cleaning Tools: These tools used to clean dirt on PCB motherboard and other Components of laptop like Fan and Keyboard …etc

Screwdrivers Tools: Most laptop systems use numerous small Phillips or Torx screws, so those drivers are the ones you’ll be using most frequently. The screwdrivers that come in some standard tool sets may be too big, so you’ll want to purchase a good set of miniature screwdrivers, or a set of miniature screwdriver bits and a handle. If slotted screws are used on a system you are working on, you need to be very careful because it is easy for the flat-blade screwdriver head to slip off and possibly damage the system. It has several screwdrivers of different shapes and sizes to disassemble and assemble a laptop.

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Soldering Tools:

Soldering Iron Used to solder small components like capacitor, resistor, diode, transistor etc. A 50 watt soldering iron is good enough for most laptop repairing job.

Gun Used to heat devices and melt solder.

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Jumper Wire Used to connect one point to another point on a PCB on the track of a laptop during repair.

Soldering Station It has option to control temperature depending on the heat requirement of the soldering job being done. The soldering iron is attached with the soldering station.

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Solder Wire Cleaner Ball Used to solder electronic components. Used to clean soldering iron tips.

Flux Used for cleaning metal surfaces before soldering them together. Because any oxides that remain on a metal surface can result in poor.

BGA Rework Station Specialised tools used to pick up and position often tiny components. Rework is the term for the refinishing operation or repair of an electronic printed.

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Kapton Tape Heat high temperature resistant Adhesive gold tape for electric task.

Solder wick To desolder electronic components and to remove excess solder from PCB Track.

Solder Sucker BGA Reballing Kit Solder pump, is a mechanical vacuum Used to reball and repair Ball-Type pump. It sucks the solder away from IC. the solder joint.

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Bios I/O KBC Programmers:

EEPROM Programmer MiniPRO TL866CS USB universal flash EEPROM programmer used to reprogram ic‟s (bios).

BGA Rework Station Designed for writing and reading multicontrollers like KB9012 and KB9010, NPCE388…

Adapter for 1.8V SPI Flash Designed for writing and reading Designed for reading and EDID EEPROM in LED-LCD 30 and writing 1.8V SPI flash W25Q32FW, 40 pin, you can fix white screen error W25Q64FW, MX25U6473f & other and brightness control errors. compatible like a 3,3V SPI flash. Laptop screen EDID EEPROM cable

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ESD Safe Tools:

ESD Wrist Strap Used to prevent electrostatic discharge by safely grounding a person working with electronic equipments or at an electronic assembly facility.

ESD Gloves Gloves provide general protection of products in massive particulation and electrostatic sensitive work areas.

Silicone Desk Mat Anti-Static Mats Several hole location to set screws, IC Anti-static mats have a high electrical chips and small parts. resistance. They allow ESD to flow across the surface at a slow rate which neutralizes the ESD.

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Inspection Tools:

Illuminated Magnifier Table Lamp Magnifying Glass Magnification lens makes seeing tiny To get magnified view of PCB and parts easy. components.

USB Digital Microscope Gives you a live image that is very similar to what you would see with a traditional dissection microscope.

HDMI Digital Microscope Allow you to view live images, as stand alone monitor watching the enlarged views on the built-in LCD.

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Electronic measuring tools:

Fluke Digital Multimeter An electronic measuring device that has the ability to measure voltage, current and resistance. It is used to test and check the readings of various parts and components of a laptop.

Oscilloscope Is an instrument that is used as a graph displaying device of an electrical signal. The graph will show how signals change over time.

Tweezers Digital Tester Capacitor Designed to accurately measure small Used to measure capacitance and chip components. help us to determine if a capacitor is functioning at the right value.

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Laptop Battery Tester Laptop battery tester which is a very important tools in laptop repairing, it can be used to test and charge any laptop batteries and check capacity, voltage, current of brand laptop battery.

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Gripping Tools:

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Tweezers Used to hold electronic components (ICs, jumper wire etc) While soldering and desoldering.

BGA Rework Station Used to pick up manipulate small parts electronic components.

Others Tools:

Laptop DC Power Adapter Kits

DC plugs power converter, match with external laptop DC power.

Digital DC Power Supply

Supply DC electricity we used to Detect Shorted component in motherboard.

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Solvent Bottle Spills & evaporation of alcohol and cleaning solvents.

Thermal Paste Application of thermal paste is essential to keep the processor cool.

IR Thermometer : Used to Measures surface temperatures that are out of reach or too hot to touch.

You now know the main tools that are used to repair a laptop motherboard. In the next part we shall take tour discuss laptop hardware.

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Part 2 Laptop Parts Tour

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Basic laptop hardware tour Hardware is the Laptop’s physical part, the stuff you can touch, the software consists of instructions that makes the hardware to do stuff. The various parts of a laptop are the Hinges (LCD display stand), Camera cable, Wifi antenna, Speakers, Palm rest or Top cover, CPU and GPU cooling fan and heat sink assembly, AC Adapter, Hard disk caddy/case, DC power jack, CMOS battery, Finger print reader, CPU socket, Battery release latch, USB mini board cable, USB mini board, mini PCI wirelessboard, Modem board, LED board, VGA board, Bluetooth board, Infrared board, LCD backlight inverter board, Power button board, Audio board.

Laptop case The laptop case serves mainly as a way to physically mount and contain all of the actual components inside of a laptop, like the motherboard, hard drive, optical drive, floppy disk drive, etc. Cases can come in many different sizes. The size and shape of a laptop case is usually determined by the form factor of the motherboard, since it is the largest component of most laptop.

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Motherboard The motherboard also known as the Mainboard or Logic Board or System Board, the motherboard is the main circuit board inside the laptop which holds the processor, memory and expansion slots and connects directly or indirectly to every part of the laptop, laptop system boards come in thousands of different shapes and sizes.

Laptop motherboards are model-specific, you can’t remove motherboard from an Acer laptop and stick it into a HP laptop.

RAM memory cover door Plastic cover door, RAM Memory Cover door used to protect RAM.

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DVD/CD-RW drives Removable media drives known as an Optical Disc Drive which allows it to read and write data from or to a CD/DVD disc, all laptop CD/DVD drives are shaped the same but they all have different face plates know as front Bezels, there are three types of optical drives: Compact Disc (CD), Digital Versatile Disc (DVD) and BluRay Disc (BD).

Different types of connectors found in modern CD/DVD optical disc drives, One drive has a SATA and the other one has an older slim ATAPI connector and other with IDE connector.

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Battery Laptop has a battery pack which provides power to the laptop while it‟s not connected to the wall-plug through AC/DC power adapter, laptop batteries come in many different shapes and they are model-specific, the laptop battery life depends upon many conditions and circumstances: screen brightness, intensity of running programs, the temperature of the working environment, etc. Current batteries have aperiod of between 2 and 10 hours.

Types of Batteries Different types of batteries use different types of chemicals and chemical reactions Some of the more common types of batteries are: Lithium-ion battery: These batteries are found in laptop, call phones and other high-use portable equipment. Nickel-Cadmium: (NiCad) batteries were the first type of battery commonly used in laptop and older laptop sometimes still use them, they have a life of roughly two hours between charges, but this life decreases with each charge based on the memory effect, gas bubbles form in the cell plates, reducing the total amount of available cell space for recharge.

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The only way around this is to discharge the battery completely before recharging it. The other drawback of NiCad is that if the battery charges too long, it can explode. Nickel-Metal Hydride: (NiMH) batteries are the bridge between NiCad and the newer Lithium-Ion (Lion) batteries. They last longer between charges than NiCad but overall have a shorter total lifespan. They suffer from the memory effect, but to a lesser extent than NiCad batteries.

Power Adapter AC adapters provides converts the high voltage AC power from a wall outlet into the low voltage DC power needed for laptop. The AC/DC adapter provides power for the laptop and charges the battery.

It‟s very important to use the right adapter for laptop, the output voltage must be the same, the amperage could be the same or higher than on the original power adapter.

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Keyboard Keyboard which is used to enter commands, text, numerical data and other types of data by pressing the keys on the keyboard.

The palm rest is the top cover for the laptop which is responsible for holding the laptop's keyboard and touch pad.

Laptop memory it is used most often to identify fast, temporary forms of storage. If your laptop's CPU had to constantly access the hard drive to retrieve every piece of data it needs, it would operate very slowly. When the information is kept in memory, the CPU can access it much more quickly. Most forms of memory are intended to store data temporarily.

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The CPU accesses memory according to a distinct hierarchy. Whether it comes from permanent storage (the hard drive) or input (the keyboard), most data goes in random access memory (RAM) first.

Types of memory Read-only memory (ROM) ROM is non-volatile, meaning it holds data even when the power is ON or OFF. Random access memory (RAM) RAM is volatile, meaning it holds data only when the power is ON (only while the laptop is running). When the power is OFF, RAM's contents are lost.

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Some laptop had RAM installed in the motherboard as individual chips.

We have different varieties of RAM in laptops and they can be of DDR1, DDR2, DDR3 or DDR4 types and they all come under the SDRAM category. When you want to know the laptop RAM difference, you must understand that though all the four types of RAM do the same function in providing the memory support to your laptop during its operation they have some vital differences both in physical design and performance design.

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DDR Old DDR 1 work with 2.5 VDC or 2 VDC DDR 2 DDR 2 work with 1.8 VDC

DDR 3 DDR 3 work with 1.5 VDC

DDR 4 DDR 4 work with 1.2 VDC

Hard drive Older laptops use IDE hard drives, newer laptops use SATA and SSD hard drives, SATA, SSD and IDE drives are not interchangeable. Hard drives are manufactured with different interfaces that are used to connect the drive to the laptop. mSATA SSD

IDE Hard Drive

SATA Hard Drive

SATA 3 SSD Drive

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Connection interface on the drive must be the same as the controller on the motherboard.

Hard Drive Caddy's with Connectors

Some common drive interfaces: Solid-State Drives An SSD is flash storage. It has no moving parts. So unlike on a traditional mechanical hard drive. Integrated Drive Electronics (IDE) also called Advanced Technology Attachment (ATA) is an early drive controller interface that connects computers and hard disk drives. An IDE interface uses a 40-pin connector. SATA Serial ATA refers to the serial version of the ATA drive controller interface. SATA interface uses a 7-pin data connector.

Storage chips (No mechanical parts)

An SSD fromSanDisk

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Difference between SATA and IDE drive

SATA drive

IDE drive

TouchPad – TrackPad A TrackPad or (Touchpad) is a touch-sensitive interface surface that allows you to manipulate and interact with your laptop through finger gestures, as laptops typically do not include mice, the TrackPad provides an alternative way to move the cursor around the screen, select and open applications or programs, highlight text, interact with web browsers and more.

TouchPad - TrackPad

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Mouse buttons A mouse button is a micro switch on a laptop mouse which can be pressed (clicked) to select or interact with an element of a graphical user interface.

Laptop screen A laptop screen displays an image generated by the laptop video card. The laptop screen receives data signal from the video card through the LCD cable, laptop screens come in many different sizes and resolutions. Liquid Crystal Display (LCD) technology has been used in laptops for some time.

LCD - CCFL Screen does need an inverter

A backlight lamp also known as CCFL bulb is the main source of light in any LCD screen.

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LED Display (light-emitting-diode display) is a screen display technology that uses a panel of LEDs as the light source.

LED Screen

Some new laptop have touch screen

Touch Screen

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Screen inverter Laptop inverter boards know as LCD inverter, FL inverter, screen inverter, backlight inverter come in different shapes and sizes.

Inverter

The inverter board works as a Power Supply for the backlight lamp mounted inside the LCD screen, The inverter board converts low voltage DC power supplied by the motherboard to high voltage AC power needed for the backlight lamp. When the inverter board works properly the backlight lamp gets power and the LCD screen lights up. As a result, the image on the screen is bright.

Screen cable A laptop LCD cable known as Video Cable, Display Cable or Screen Cable, this cable transfers data signal from the motherboard and video card to the LCD screen.

Video Cable with Webcam Cable

Video LVDS Cable

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Web camera Web camera is another input device, new laptop come with a build-in web camera also known as webcam. The web camera is located on the top of the display panel.

Web camera

CPU Fan A CPU cooling fan is a dedicated fan which cools down the heatsink and eventually the CPU (Processor), usually the CPU cooling fan comes as a part of the heatsink assembly a metal part drawing heat from the CPU chip, in addition to the CPU cooling fan, some laptops have a dedicated GPU Graphics Processing Unit fan which cools down the GPU chip. The CPU and GPU cooling fans connect directly to the motherboard via a cable running from the fan, when CPU and GPU chips get hotter the cooling fan spins faster.

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FAN - HeatSink

CMOS battery The CMOS battery connects directly to the laptop motherboard and helps to retain important BIOS settings such as system time, date, BIOS configuration while the laptop is turned off or even when the main battery is removed, the CMOS battery is rechargeable and it’s getting charged when the laptop is plugged into the mains.

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CPU Central Processing Unit The processor is the main brain or heart of a laptop system. It performs all of the instructions and calculations that are needed and manages the flow of information through a laptop. Both Intel and AMD, the largest microprocessor manufacturers in the world, have introduced several types of computer processor, each processor type is different from the other in performance and technology.The latest Intel Core i Series processors: i3, i5, i7, i9 and AMD Phenom family processors are among high-end CPU’s.

AMD CPU

Intel CPU

LID close switch The lid close switch is a small button that locates close to the display hinges. On some newer models there is no button, because the switch is magnetic. You can set up your laptop to go to a hibernation mode or to a standby mode when the LCD is closed. It’s done through power management software. These modes are triggered when the display is closed and the lid close switch is pressed down.

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Front bezel Screen bezel is the area of a display that surrounds the screen. Thinner bezels help maximize the screen real estate of a laptops.

Cover-Lid with Wi-Fi Antenna The Wi-Fi antenna is located in the top or the bottom of the LCD display housing. It consists of two elements, fed by two cables, a white main designated on the Wi-Fi card by a white triangle, and a black auxiliary designated on the Wi-Fi card by a black triangle.

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Wi-Fi cards The Wi-Fi card acts as both a receiver and transmitter. It receives the wireless signal and communicates with the wireless network, enabling you to access the Web with your laptop.

Hinges rails Two pieces of metal that are cut in specific patterns are fit together and have a round pin where they connect that allows them to rotate against each other in a limited way. The hinge needs to avoid stressing the plastic lid at the points where it is screwed in, but different companies have different ways of handling this.

Hinges Rails Right and Left

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Hinge covers Laptops have a plastic cover that hides the hinge mechanism.

SD card reader Card reader is a device for accessing the data on a memory card. Built-in card reader in a laptop is the best option if you often copy files to and from a SD card.

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Power button board The power button used to power a laptop (on) and shutdown laptop (off).

Other hardware parts USB - HDMI - Audio - DC Jack - Power Button - IO Boards

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Motherboard overview

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North bridge chip AMD CPU

VGA Chip

RAM Slots VGA Memory Chip Memory Chip

CMOS Battery

South bridge chip

VGA Memory Chip Memory Chip

RAM Slots

VGA Chip CPU Socket

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Super I/O

EEPROM (BIOS IC) South bridge

VGA Memory Chips

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10 YouTube Channels to Follow for Tech Laptop Disassembly 10 of the Best YouTube Channels for learning disassembly laptop selected from 100 of channels on YouTube and ranked based on YouTube channel subscribers and popularity.

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365 Laptop Repair

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LaptopRepairHelp

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Parts-People.Com, Inc

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LaptopScreencom

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Laptop disassembly

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FastVideoTech

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Notebook-Center

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JackFixit

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LaptopProject

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hone Laptop Repairj500j500

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Part 3 Basic Electronics

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The goal of this part is to provide some basic information about electronic components.

What is Electricity? Electricity is a form of energy caused by charged atomic particles. It can build up in one place or move from one place to another. When it’s not moving it’s called “static electricity” and when it is moving it’s called “current electricity” or electrical current.

What is an Electron? Everything you see around you is made of Electron atoms, which are particles so small you can’t Proton see them without a special type of Neutron microscope. But atoms are made of even smaller particles, called protons, neutrons, and Nucleus electrons. Protons and neutrons forman atom’s nucleus (its center), and electrons orbit the nucleus like planets orbiting the sun. Protons and electrons are both electrically charged: protons have a positive charge, and electrons have a negative charge. That’s why Atom the electrons stick with an atom in the first place. The positive and negative charges act like opposite sides of a magnet and attract each other. Certain materials are conductive, which means that if you apply energy to them (like the energy stored in a battery), the electrons will start moving from one atom to the next! The filament inside your light bulb is made of a conductivemetal, meaning it’s full of electrons just waiting for a push to move them.

Current: Given an appropriate external force, the movement of electrons is from negatively charged atoms to positively charged atoms. This flow of electrons is called current (I). The symbol I is used to represent current. The amount of current is the sum of the charges of the moving electrons past a given point.

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An electron has a very small charge, so the charge of 6.24 1018 electrons is added together and called a coulomb (C). When one coulomb of charge moves past a single point in one second it is called an ampere (A). The ampere is named for a French physicist named André Marie Ampère (1775-1836). Current is measured in amperes.

Voltage: When there is an excess of electrons (negative charge) at one end of a conductor and a deficiency of electrons (positive charge) at the opposite end, a current flow between the two ends. A current flow through the conductor as long as this condition persists. The source that creates this excess of electrons at one end and the deficiency at the other end represents the potential. The potential is the ability of the source to perform electrical work. The actual work accomplished in a circuit is a result of the difference of potential available at the two ends of a conductor. It is this difference of potential that causes electrons to move or flow in acircuit. The difference of potential is referred to as electromotive force (emf) or voltage. Voltage is the force that moves the electrons in the circuit. Think of voltage as the pressure or pump that moves the electrons. The symbol (E) is used in electronics to represent voltage. The unit for measuring voltage is the volt (V), named for Count Alessandro Volta (1745–1827), inventor of the first cell to produce electricity. Electrons flow in a circuit because of the difference of potential.

Difference of potential

Load

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Resistance: As the free electrons move through the circuit, they encounter atoms that do not readily give up electrons. This opposition to the flow of electrons (the current) is called resistance (R). Every material offers some resistance or opposition to current flow. The degree of resistance of a material depends on its size, shape, and temperature. Materials with a low resistance are called conductors. Conductors have many free electrons and offer little resistance to current flow. As previously mentioned, silver, copper, gold and aluminum are examples of good conductors. Materials with a high resistance are called insulators. Insulators have few free electrons and offer a high resistance to current flow. As previously mentioned, glass, rubber and plastic are examples of good insulators. Resistance is measured in ohms, a unit named for the German physicist George Simon Ohm (1787–1854). The symbol for the ohm is the Greek letter omega (Ω).

Voltage Pushes Electrons: When you attach a battery to the light bulb, you’re applying a voltage across the filament inside. Voltage pushes electrons through the wire and is measured in volts (V). The higher the voltage, the more electrons will flow through the wire. Think of a wire like a tube filled with marbles: when you put a marble in on one side, a marble pops out on the other side at the exact same time, with no delay.

Voltage electrons

The more marbles you push in one side, the more pop out of the other. That’s how electrons be have inside a wire, when a voltage is applied to them.

Current Flows: Current is the number of electrons flowing through a wire,and it’s measured in amperes (A), which we usually shorten to amps. You might have also heard the word current used to describe a river, as in “This river has a strong current.” That means there’s a lot of water moving down the river.

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Electrical current is similar: a strong current means there are a lot of electrons flowing through a wire. When you increase the voltage in a circuit, the current also increases. Just as water flows downhill due to gravity, electric current flows from the positive battery terminal toward the negative battery terminal. Actually, the electrons themselves flow in the opposite direction, from the negative side of your battery to the positive side. But when we talk about electrical current, we say that it flows from positive (+) to negative (–). Current

Positive

Electrons

Negative

Resistance reduces current: Voltage pushes electrons to form a current, and resistance restricts the current. It’s like playing with a garden hose: if you squeeze the hose, you add resistance to the flow of water so that less water comes out. But if you turn the tap more (like increasing the voltage), the pressure increases, and more water flows even though you’re still squeezing the hose in the same way. Resistance in electricity works just like this, and it’s measured in ohms (Ω).

Resistance

Resistance

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Types of current: There are two types of current. Alternating current (AC) refers to an electrical charge that moves back and forth through circuits at a specific rate. It usually has much higher voltage and is much more dangerous. AC is used by anything that plugs into a wall outlet. Remember, don’t experiment with alternating current from a wall outlet or power strip-it can seriously hurt you!

AC currentsymbol

Direct current (DC) flows in one direction. Typically, anything that is powered by a battery or has a circuit board inside, such as your cellphone and laptop uses DC.

DC currentsymbol

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How do we measure electricity? Electricity can be measured in these three ways:

Current Measured in amps (A), current measures the amount of charge in a circuit over a period of time. The symbol for current is (I), which comes from the French intensité de courant (meaning “current intensity”).

Voltage Measured in volts (V), voltage measures the force causing the electrons to travel. Stated differently, it measures how much potential energy exists between two points in a circuit.

Resistance Measured in ohms (OH-mms) (Ω), resistance measures how hard the electrons have to be forced to move through a circuit.

Ohm’s Law: The current that flows in a circuit is directly proportional to the voltage and inversely proportional to the resistance. This relationship is called Ohm’s law and can be expressed in a formula as I = V / R. This is the most important and basic property in electric circuits. For example, if a voltage of 120V is applied to a resistance of 120Ω, the current will be I = V / R = 120/120, and 1A of current will flow. Whenever you know two values among the current, voltage, and resistance in a circuit, you can use Ohm’s law to calculate the valueyou don’t know.

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Power (P)

Voltage (V)

The total work performed by a current

Electrical force or pressure

Current (I)

Resistance (R)

The number of electrons passing in a single point

Resistance to the flow of current

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Effective Resistance: There are two basic methods of connecting electrical components. Let’s look at them both with respect to resistance. When there are multiple resistances in a circuit, we can consider them as a single effective resistance. The method of connecting resistances in a line is called a series connection. We calculate the value of the effective resistance in a series connection by totaling the individual resistance values. Effective resistance = R0 = R1 + R2 + ... + Rn In this connection the size of the current that flows in each resistance is the same. The power supply voltage is voltage divided by each resistance. Effective Resistance

R0 = R1 + R2+ R3 + … + RN Series Connecton

R1

R2

R3

RN

V1

V2

V3

VN

Power supply voltage

Calculate power supply voltage by dividing voltage the sum of the resistances

Series connection and effective resistance If two light bulbs of the same size are connected in series to a power supply, the current will be halved, and the brightness of each bulb will be dimmer than it was when just a single bulb was connected, because the effective resistance is doubled. At this time, the voltage at both sides of each light bulb will be half the value of the power supply voltage.

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Two bulbs connected in series Current

Current

Bulbs now shine more dimly, because current to the bulb is half what it was. Series connection of light bulbs The other basic method of connecting resistances is called a parallel connection. At this time, the value of the effective resistance can be obtained by calculating the reciprocal of the sum of the reciprocals of each resistance. 1

Effective resistance = R0 = 1

1

1

R1

R2

RN

The total resistance when two resistances are connected in parallel can be obtained as follows. Effective resistance = R0 =

R1 * R2 R1 + R2

In a parallel circuit, the voltage applied to each resistance is the same, because the current branches and flows to each resistance.

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Current branches to each resistance

Parallel connection

Effective resistance 1

Current

R0 = 1 + 1 + 1 +…1 R1 R2 R3 RN Voltage applied to each resistance is the same.

Power supply voltage

Parallel connection and effective resistance If two light bulbs of the same size are connected in parallel to a power supply, the brightness of each bulb is the same as it is when there is only one bulb. Since the current flowing to each bulb is the same as the current flowing when only one bulb is connected, the total current is doubled. One light bulb Current

Two bulbs connected in parallel Current

Bulbs now shine with the same brightness, since total current is doubled. Series connection of light bulbs The 220V electric appliances that we use in our homes are connected in parallel to a 220V power supply. If we increase the number of electric appliances connected to the power supply, the total current flowing also increases.

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Binary Number System: Normally, when you talk about numbers, you use decimal numbers, which are in the base-10 number system. In base-10 numbers, a digit can have one of 10 possible values, from 0 to 9. But digital circuits can work with only two voltages (high and low), so they can understand only binary numbers. Binary is also called the base-2 number system, and a binary number’s digits have only two possible values: 0 and 1. Here’s how you’d count to 10 in both decimal and binary:

Decimal Number 0 1 2 3 4 5 6 7 8 9 10

Binary Number 0 1 10 11 100 101 110 111 1000 1001 1010

What’s going on here? The number 2 in decimal is 10 in binary and 4 in decimal is 100 in binary! You can figure out the value of any number in any system using the digits and their position. The right most digit always gets multiplied by 1. Going left from there, each position’s value equals the base times the value of the previous position. In decimal, the base is 10, so the second position’s value is 10, or 10 × 1; the third position’s value is 100, or 10 × 10; the fourth position’s value is 1000, or 10 × 100; and so on. Here’s an example:

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Multipy by 10 Multipy by 100

Multiply by 1

181 100x1

10x8

1x1

100 + 80 + 1 = 181 In the number 181, the first digit is 1, the second digitis 8, and the third digit is 1. Once you multiply those digits by their position values, you can add the resulting values toget 181. You don’t need to use this method to figure out decimal numbers, though. It’s pretty clear that 181 equals 181! But this method is very useful for finding the value of binary numbers. Binary follows the same rules, but it uses a base of 2 instead.

Bits and Bytes: Each digit in a binary number is called a bit (that’s short for binary digit), and computers handle numbers in blocks of eight bits called a byte. The binary number 1011 0101 has eight bits, so it’s a byte. You can interact with a computer in many ways, but all your mouse clicks, key presses, webcam videos, and soon need to be translated into bits and bytes before the computer can understand them. In fact, when working with computers and other digital gadgets, you usually see much, much larger numbers than just 1 byte. All the files on a computer are collections of bytes, but if you tried to describe their size in bytes alone, those numbers would be huge! That’s why files are usually described in larger units, like kilobytes (kB), megabytes (MB), gigabytes (GB), terabytes (TB), and so on. Here’s what those units mean: 1 KB = 1,000 bytes 1 MB = 1,000 kB = 1,000,000 bytes 1 GB = 1,000 MB = 1,000,000 kB = 1,000,000,000 bytes 1 TB = 1,000 GB = 1,000,000 MB = 1,000,000,000 kB = 1,000,000,000,000 bytes If a computer’s hard disk can hold 1 TB of data, then it can hold one trillion bytes, which is eight trillion ones and zeros!

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Logical: Logic is a way of reaching a conclusion based on pieces of information that you know to be true or false. For example, imagine you know the following statement is true, beyond a doubt: Statement 1: If there are oranges inyour fridge and you have an orange squeezer, then you’re able to make orange juice. If you trust the preceding statement, then there are two conditions to check before you can make orange juice: Condition 1: There are oranges in your fridge. Condition 2: You have an orange squeezer. If you check your kitchen and find that these conditions are true, then you can logically conclude that you can make orange juice. Computers use Boolean logic, which is a system of logic that works only with the values true and false to convert ones and zeros into actions. For a computer to know whether you can make orange juice or not, it would have to reach that conclusion through Boolean logic. Let’s try thinking like a computer! First, look for the conditions in Statement 1 that affect whether you can make orange juice or not. In this case, the conditions are the two phrases between “if” and “then,” joined by “and.” Assign them letters as follows: There are oranges in your fridge. = A You have an orange squeezer. = B The conclusion is the statement after “then.” Give it aletter, too: You’re able to make orange juice. = Q With these letters, you could rewrite Statement 1 as “If A and B, then Q.” In Boolean logic short hand, that looks like this:

A AND B = Q

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This is a logic equation, where AND is an operator like addition or subtraction. When both statements on either side of AND are true, the conclusion Q is true. Given Condition 1 and Condition 2, A and B are both true. Substitute both into the equation to get:

True AND True = Q Q = True Because both A and B are true, then Q must be true. Time to make orange juice! How a Computer Decides When It Can Make Orange Juice Condition A (There are oranges in your fridge.)

Condition B (You have an orange squeezer

Result Q (You’re able to make orange juice.)

False

False

False

False

True

False

True

False

False

True

True

True!

Logic Gates: Many of the circuits inside your computer are physical versions of logic equations, complete with smaller circuits called logic gates, which are physical logical operators. A logic gate takes ones and zeros-representing true and false, respectively-as inputs and then outputs a 1 or 0 based on the results of the equation inside.

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AND Gates Check for Two True Inputs: The AND gate is the physical form of the AND operator you used to decide whether you were able to make orange juice. An AND gate has two or more inputs - A and B, for example - and one output - Q, for example. It checks whether A and Bare both 1, and if they are, then Q is 1; otherwise, the output is 0. Q is 1 only if both A and B are 1; if one or both inputs are 0, the output is 0. I find it helpful to write out the values of Q that result from different input combinations in a truth table. This truth table shows all possible input combinations for the AND gate and what the output will be for each. In a truth table, 0 standsfor false, and 1 stands for true.

AND gate

A B

A O O I I

Q Symbol

B O I O I

Q = A AND B O O O I

Truth table

OR Gates Check for One True Input: The OR gate checks whether input A or input B is 1. If either is 1 or both are 1, then the output Q is also 1. But if both inputs are 0, then the output is 0.

OR gate

Input

Output

A B

Q Symbol

A B Q + A OR B O O O O I I I I I I O I Truth table

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NOT Gates Flip Inputs: The NOT gate, also called an inverter, has only one input and one output, and its function is very simple: the output is the opposite of the input. If the input is 1, then the output is 0. If the input is 0, the output is 1.

NOT gate Output

Input A

Q

A

Q = NOT A

O

I

I

O

A Bigger AND Gate: AND gates and OR gates can have more than two inputs. For example, here’s a 4input AND gate symbol: 4-input AND gate

A B

Q

C D

Because it’s an AND gate, the result will be 1 only if all four inputs are 1; otherwise, it will be 0. That is, the output Q is true (1) if all four inputs—A, B, C, and D—are true (1):

Q = A AND B AND C AND D We can also make a 4-input AND gate from three 2-input AND gates, like this:

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4-input AND gate

A B Q C D

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Part 4 Electronic Components

types and functions and Test

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The Main Electronic Components in Laptop Motherboard 1

Capacitor

2

Resistor

Limit the flow of electrons, reducing current

3

Inductor

Resists changes in the electrical current when passing through it

4

Fuse

Protects the circuit from the risk of increasing electricity current

5

Diode

Allows the electric current to pass in one direction only

6

Crystal oscillator

Generates a very precise frequency electrical signal at a specified time

7

Transistor

Transistors are used when it is necessary to amplify voltage, current, and power.

8

IC

An integrated circuit is a collection of electronic components (resistors, transistors,capacitors, etc.)

Stores an electrical charge for a short period of time

The electronic components shown in the figure above are the main components you will find in the laptop motherboard, but you will find them in the form of different shapes and sizes, according to the design of the electronic board.

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We’re going to give you a brief overview of common electronic components and explain what their functions are, units of measurement and methods of testing them.

Capacitor The capacitor is like a rechargeable battery; you can charge a capacitor and use its energy to power something. But a battery can hold much more energy than a capacitor. A battery can power an LED for days without recharging, while most capacitors can power one for only a few seconds at most.

How Capacitors Work: On the inside, capacitors are very simple devices. They’re made of two metal plates placed very close together, with a material such as paper in between. To save space, the metal plates and the material between them are folded or rolled into a compact package.

Terminal

Metal Plates Dielectric (material to keep plates apart, such as paper)

Capacitor

Dielectric (material to keep plates apart, such as paper)

Capacitor used for many purposes: - Storing and discharging the current according to the needs of the Electronic circuit - The link between electronic circuits - Smoothing the electrical current

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Typesof Capacitors You will notice that there are several typesof capacitors:

Electrolytic Capacitors

Plastic Film Capacitors

SMD Ceramic Capacitors

Ceramic Capacitors

Tantalum Capacitors

SMD Tantalum Capacitors

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Aluminum Capacitors

SMD AluminumCapacitors

Photo showing three different types of capacitors

SMD Solid Capacitors

SMD Ceramic Capacitors SMD Tantalum Capacitor

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Capacitor Features: Capacitors are measured in farads or more commonly in micro farads and PicoFarads. The name comes from Michael Faraday (1791-1867) a very interesting man. Every capacitor will have two important ratings: capacitance and voltage. 1- Capacitance : Capacitance is a way of saying how much energy the capacitor can hold at a given voltage. This value measured in pico-Farads (pF), nano-Farads (nF) or micro-Farads (µF) and is marked onto the body of the capacitor as numbers, letters or colored bands. 2- Voltage : The Working Voltage is another important capacitor characteristic that defines the maximum continuous voltage either DC or AC that can be applied to the capacitor without failure during its working life. 3- Equivalent Series Resistance(ESR) : The Equivalent Series Resistance or ESR, of a capacitor is the AC impedance of the capacitor when used at high frequencies and includes the resistance of the dielectric material, the DC resistance of the terminal leads, the DC resistance of the connections to the dielectric and the capacitor plate resistance all measured at a particular frequency and temperature. Aluminum Capacitor

Electrolytic Capacitor The maximum voltage is 10v

The maximum voltage is 6.3v Capacitance rating is 1000 µF

Capacitance rating is 2200 µF

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Did You Know? When you are wanting to replacing a capacitor, you must to use the same or higher capacitance rating and same or higher voltage rating or very close to it.

SMD Ceramic Capacitors written the side it letter C with number

Non Polar Capacitor Symbol like SMD Ceramic Capacitors

Polar Capacitor Symbol like Electrolytic Capacitors

Capacitors are symbolized on mainboard with the letter C and sometimes symbolized with two letters like PC and sometimes does not have beside it any letters in some mainboard.

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SMD ceramic capacitors without voltage or capacitance value

Some capacitors don’t have the value of capacity or voltage value written on them like ceramic capacitors.

Did You Know? When SMD ceramic capacitor is damaged, you can replaced with another SMD ceramic capacitor by same size and will function without the any problem. Polarized Capacitor Can only be connected to a circuit in one direction must be inserted in the proper orientation with respect to applied voltage. If a polarized capacitor was connected to a circuit incorrectly, at best it won’t work as intended. At worst, an incorrectly connected polarized capacitor will smoke, spark, and be one very dead part.

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PolarizedCapacitor Electrolytic Capacitor

SMD Tantalum Capacitor

SMD Tantalum Capacitor

Aluminum Capacitor

Non-Polarized Capacitor mean that they can be inserted into a circuit around either way.

Non Polarized Capacitor SMD Ceramic Capacitors

Tantalum Capacitors

Plastic Film Capacitors

Ceramic Capacitors

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Positive Side

Negative Side

+

Bar across one end of this tantalum capacitors provides the capacitor positive lead polarity

White line drawn on motherboard show you the positive tantalum capacitor

Bar show direction of the positive tantalum capacitor

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Non-polar capacitors like ceramic capacitors which have no specific orientation for installation on the motherboard we can install them in both directions

Ceramic capacitors without a specific direction because this is non-polar type can be installed in both direction

Capacitores NEC Proadlizer Proadlizer capacitor is a group of capacitors grouped in one package and Manufacturer use this capacitor to reduce the cost of production and the area occupied by components in the motherboard design.

33 Capacitors(4 aluminum+29 ceramic)

1 CapacitorProadlizer

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Capacitors testing There are three main ways to test capacitors. 1- Visual inspection: This is the first thing must be done when you repair any laptop motherboard, we should check the electronic components to make sure that there are no traces of burning or roasting on any electronic component, first scan around the motherboard looking for capacitors which has its top will either swell or burst open. the upper surface of the electrolytic capacitor is inflated

In this case, you do not need to check the capacitors, just direct replace it and retest the motherboard.

84 2-

Using Digital Capacitance Meter

Digits LCD Display

Zero adjustment+- 20pF approx 9 test ranges from 200pF to 20mF

Be sure that capacitor is fully discharged before tested

Socket use it to plug leads of capacitor directly for measurement

Test leads put RED one into positive lead of capacitor and put BLACK lead into negative of capacitor

3- Using ESR Meter This is the latest technology in testing capacitors. It is used to check on electrolytic capacitors and the advantage is that you can perform capacitor testing while the capacitor is still in circuit, it can test aluminum electrolytic capacitors, film capacitors, ceramic, high voltage capacitors, etc. It also has the function to check inductors and coils too.

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4- Using Digital Multimeter

Using the Continuity test or the Buzzer mode

Testing SMD Ceramic Capacitor

1) Put the two ends of the measurement on the ceramic capacitor. 2) Shows value without sound of a buzzer so ceramic capacitor is Good.

1) Sound of a buzzer with 0 value so capacitor is damage (short circuit)

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Resistor A resistor is a passive electrical component with a primary function to limit the flow of electric current, adjust signal level, to divide voltages, resistors come in different shapes and sizes. We measure the amount of resistance with aunit called Ω ohms.

Figure 1 Resistance

Figure 2 SMD Resistor

Have colored bands on them

Tiny surface mount resistor

Figure 3 SMD Network Resistor A group of resistors have the same value in a single package. They primarily act as a voltage divider, which split the voltage in a circuit to smaller amounts. Whether you want a thick film resistor array or thin film resistor array, find them in great price range at Future Electronics. We are the reputed distributor of resistor networks from leading brands.

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SMD Resistors with letter R, numbers and letter on their surface indicating their value

Zero Ohm resistance, used as a connection between two points on the motherboard (it function as a fuse)

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On the Motherboard the symbol for resistors is usually present by letter R, an example is the R5 & R9, R10 on the motherboard below.

On the Schematic diagram the Resistor symbol is usually present by

Understanding the Resistor Code: When you look at a resistor, you’ll notice that it has several colored bands. These colors tell you the value of the resistor, to find the value of a resistor, use the table below.

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Most resistors have four color bands. From the left, the first band gives the first digit of the resistance value. In this example, the first band is yellow, so the first digit is 4. The second digit is given by the second band, which is violet for 7. Together, this gives us the base value of 47. Next we multiply 47 by the value of the third band—the multiplier. In this example, the orange band stands for 103 Ω, so we multiply 47 by 1000: 47 × 1000 Ω = 47000 Ω = 47 kΩ

Note: If a resistor has five bands instead of four, then the first three bands are digits, and the fourth is the multiplier. But the actual resistance of a resistor usually won’t match the value written on it! That sounds a bit crazy, right? It’s hard for manufacturers to create resistors with a very exact resistance value, so instead, they make sure the resistors are some where around that value and tell you how far off the real value could be. This is where tolerance comes in. Our example resistoris labeled 47 kΩ with a tolerance of 5 percent. This means that the resistor’s real resistance could be any value 5 percent higher or 5 percent lower than 47 kΩ. Because 5 percent of 47 is around 24, the real resistance could be anywhere between 43 kΩ and 49 kΩ. Usually, the three bands that tell you the resistance value are grouped together, and the band that tells you the tolerance is spaced a bit farther away. But sometimes the bands are so close that it’s hard to see which three bands give the resistance. Fortunately, the fourth band is typically gold or silver, so if you see a gold or silver band, it’s safe to assume this is the tolerance band.

How to Write large values Our resistance color chart shows some resistance values written with k and M in front of the Ω symbol. These are part of a short hand that makes it easier to write really large values. If you have a resistor that’s 300,000 Ω, it’s common to shorten that to 300 kΩ instead, where k is short for kilo, which means one thousand. The M stands for mega, which means one million. So instead of writing 3,000,000 Ω you could write 3 MΩ.

You can use online website or program to calculation of resistor value. https://www.digikey.com/en/resources/conversion-calculators/conversioncalculator-resistor-color-code-4-band

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Resistor Testing 1- Visual inspection: Checks for missing or any burning on resistance.

Example of Burnt resistances

2- Using Digital Multimeter: You can check the resistor resistance by selecting the ohm range in the digital multimeter, If the resistor is in circuit, you will generally have to remove the resistor so you are testing only the resistor value and not the other components in the circuit.

Set the dial to resistance mode

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Connect test probes across the two points of the resistor as shown in the photo, polarity isn’t important, value of resistance shown is 9.86 kΩ.

Note: All resistors have a specific tolerance rating. The tolerance rating is marked by a color band on the end of the resistor’s body, normally the band is gold indicating 5 % tolerance. If the tolerance band is silver, then the rating is 10 %.

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How to test SMD Resistors: Because of the small size of SMD resistors, there is often not room for the traditional color band code to be printed on them. Therefore, new resistor SMD codes were developed. The most commonly seen codes are the three and fourdigit system and an Electronic Industries Alliance (EIA) system called EIA-96.

Examples of 3 and 4 Digits coding system

Examples of Digits coding systemEIA-96

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Let’s take an example of a 3 and 4 Digit System: In this system the first two or three digits indicate the numerical resistance value of the resistor and the last digit gives a multiplier. The number of the last digit indicates the power of ten by which to multiply the given resistor value. Here are some examples of values under this system:

Significant Value

Multiply Factor

This example, value of resistance is

792 X10º = 792 X 1= 792 Ω

The R or decimal between 2 and 3 which means the value of = 2.3 Ω

Significant Value

Multiply Factor

This example, value of resistance is

31X10² = 31X 100 =3100 Ω = 31 kΩ

This resistance has the letter R as first digit represents a decimal so this resistance has a value of = 0.382 Ω

This resistance has the only a zero and represents a zero-ohm resistor with no resistance.

This resistance has 3 zero and also called a zero-ohm resistor with no resistance.

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Select Ohms range and place your test probes across the two points of the SMD resistance as shown in the photo. this SMD resistance belongs to the system of coding 3-4 Digits System by use this system coding we’ll find value of resistance: 561 = 560 ohms or 0.560 k ohms.

This resistance is 0 ohm (zero-ohm resistance) it functions as a fuse.

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The multimeter show OL that means bad resistance. Once the SMD resistors are burnt, the only way to find out the value is through a schematic diagram or comparison from the same motherboard model. Now we take a look at another popular coding method the EIA 96 System this system is based on a 96 series of preferred values.

by looking up for code of 38 in above table 1 we find the value of 243 in table 2 we find that the letter C means a multiplied factor of 100 this resistor is therefore a value of 24.3kΩ.

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The SMD resistor coding is the same as the SMD network resistor. An SMD network resistor consists of few resistors that have same ohms value in a single package.

The testing method is the same as a normal type of resistor, Calculate the SMD resistor code first, above example we have SMD network resistor marking on it number 510 its means 51k ohms. Then place the test probes across the two ends of the SMD network resistor and read the result directly from the digital meter LCD display.

Same ohms value

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Inductor - Coil An electric wire wound in loops is called a coil. If current flows in a coil, a magnetic field is generated that goes through the inside of the coil. If an iron core is inserted in the coil, the magnetic field is concentrated in the iron, and it becomes a strong electromagnet. The strength of an electromagnet is proportional to the product of the current and the number of loops in the coil, if the direction of the current is reversed, the polarity of the electromagnet is also reversed. If the current is stopped, the magnetic force of the electromagnet disappears, on the schematic diagram and on the motherboard an inductor is represented by letter (L).

Current

Magnetic field

Current

Current

Magnetic field Below are a few examples of inductors:

Inductors Types

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SMD Inductor / SMD Coil and its side is written letter L with number and sometimes written with two letters like

PL or DL

The symbol of Coil on schematic diagram

Other types of Inductor and its side is written letter PL with number

Other types o fInductor written the side it letters PL with number

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Inductor Testing Set to the buzzer mode to test an inductor with digital multimeter. If the inductor is ok, the buzzer will sound and if the inductor is open (internally) or shorted there will be no sound. Buzzer mark appears on the screen

Set the multimeter to buzzer mode

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Fuse A fuse is a very thin wire, the function of fuses is to stop higher than normal current from flowing through an electronic circuit. It is designed to protect electronic components from being damaged, fuse come in different sizes and shapes. A fuse is labeled as (F) in a motherboard.

Different types of SMD Fuse

SMD Fuse symbols on schematic diagram

SMD Fuse symbolized on mainboard & schematic diagram with the letter F and sometimes symbolized with two letters like PF, FP and next to it is a number.

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Testing Fuse Touch the probes to both end of the fuse. You can check the fuse while it still in mainboard or out of mainboard. A good fuse reading should show continuity or read ZERO ohms. A bad fuse is open which will not showany reading on your meter. You may also set to the buzzer range to test a fuse with digital meter. If the fuse is ok, the buzzer will sound and if the fuse is damage there will be no sound.

The red and black test probes can be either way when testing fuses

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Diode Diode only allow current to flow in one direction, and they’re always polarized. A diode has two terminals. The positive (-) side is called the anode, and the negative (+) one is called the cathode. They are made from silicon slabs “doped” with materialsthat cause the one-way current flow.

The diode symbol with the anode and cathode marked on schematic diagram Current through a diode can only flow from the anode to the cathode, which would explain why it’s important for a diode to be connected in the correct direction. Physically, every diode should have some sort of indication for either the anode or cathode pin. Usually the diode will have a line near the cathode pin, which matches the vertical line in the diode circuit symbol. Below are a few examples of diodes.

Diode

SMD Diode

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SMD diode use a line to mark which pin is the cathode

Diode use a grey ring to mark which pin is the cathode

Diode symbolized on mainboard and circuit diagram with the letter D. Diodes symbols on schematic diagram

Zener Diode

Schottky Diode

Silicon Diode

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SMD Dual Diode is a single package with 2 diodes, middle pin is the negative.

2

1

3

SMD Dual Diode

Don’t think these two SMD are transistors, in fact they are SMD dual diode, look at marking on the motherboard D18, D17, letter D is diode symbol on motherboard.

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Testing Diode When using digital meter, you should set your meter to Diode test range and again you should expect reading one side and when you reverse the probe you will get no reading.

Cathode

Anode

Note: In some cases, it may be necessary to remove one end of the diode from the circuit in order to test the diode. A good SMD diode should have one reading and if you get two readings that means the diode already shorted.

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Zener Diode A Zener diode allows current to flow from anode to cathode like normal diode, but it also permits current to flow in the reverse direction when its Zener voltage is reached, Zener diodes have a highly doped p-n junction. Normal diodes will also break down with a reverse voltage but the voltage and sharpness of the knee are not as well defined as for a Zener diode. Also, normal diodes are not designed to operate in the breakdown region but Zener diodes can reliably operate in this region.

Zener Diode

SMD Zener Diode

Zener diode symbol on the circuit diagram and motherboard usually begin with letter “ZD”.

Anode (+)

Cathode (-)

Zener diode symbol on schematic diagram

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Testing Zener Diode Testing a Zener diode is just like testing a normal diode, when using digital meter, you should set your meter to diode test range and again you should expect reading one side and when you reverse the probe you will get no reading.

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Transformer A transformer is a device that takes electricity turns into a magnetic field, then turns it back into electricity. Depending on how the transformer is designed, transformers are used to increase or decrease the alternating voltages in electric power applications, A transformer is labeled as “T” on a schematic diagram.

Transformer symbol

SMPS Transformer are used in switch mode power supplies in electronic equipment such as adapters of laptop and Inverter board of LCD and TVs, etc. The input is called the primary winding while the outputs are the secondary winding.

SMPS SMPSTransformer Transformer

Switch Mode Power Supply Transformer section in adapter

CCFL Lamps output voltage connector

High Voltage Transformer

Switch Mode Power Supply Transformer in Inverter board of LCD

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Crystal Oscillator A crystal oscillator is an electronic circuit that uses the mechanical resonance of a vibrating crystal of piezoelectric material to create an electrical signal with a very precise frequency. This frequency is commonly used to keep track of time, to provide a stable clock signal for digital integrated circuits. Quartz crystals are manufactured for frequencies from a few tens of kilohertz to tens of megahertz. More than two billion, you well find a crystal in a digital device like a laptop, DVD player or MP3 player.

Crystal symbolized on motherboard & schematic diagram with the letter X or Yand next to it a number YK1.

Symbol Crystalon schematic diagram

Crystal in the laptop motherboard, printed with letters YK1 and their frequencies 14.318 MHZ marked on their body.

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Crystal symbol in diagram, printed with letters YK1 and their frequencies 14.318 MHZ marked on their body.

For testing crystal oscillators, you will must have digital multimeter with Hz mode or testing by a crystal tester or use or oscilloscope. The measurement must be taken when the motherboard power is ‘On’. Put the probe of the digital multimeter or crystal to the crystal pin and read the measurement. That means place the black probe to cold ground and the red probe to the crystal pins.

Hz function in a digital multimeter

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Transistor Transistors are semiconductor devices with three terminals that can act as amplifier controls or electrically controlled switches. Amplifier: when it works as an amplifier, it takes a tiny electric input current at one lead and produces a bigger output current at the other lead. Switch: A small electric current through a lead can switch on a bigger current flow through the other leads of the transistor. In the photo below, you can see several types of transistors:

Semiconductors Transistors are made of silicon which is a semiconductor. A semiconductor is a material that is not a pure conductor, it has higher resistance than a conductor, but much lower resistance than insulators.

N-Type We can introduce impurities into silicon, so that it works in a specific way, this process is called doping. If we dope the silicon with chemical elements such as phosphorous, arsenic or antimony, which have 5 valence electrons, the silicon gains free extra electrons that can carry an electric current. When we add these elements, we are introducing electrons. As electrons are negative, this type of semiconductor is called N-Type (negative type).

P-Type On the other hand, we can dope silicon with other elements like boron or gallium. As these elements have only three outer electrons, when they are mixed into the silicon matrix, they create “holes” with absence of electrons. So, this type of silicon has less extra free electrons, and so it is called the P-Type (positive type).

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N-Type

P-Type Donorimpurityco ntributes free electrons

Acceptorimpurity creates a hole

Types of transistors Bipolar Junction Transistor (BJT)

PNP Transistor

NPN Transistor

Unipolar Junction Transistor

MOSFET

JFET

N-Channel

N-Channel

P-Channel

P-Channel

The two major families of transistors are bipolar junction transistors (BJTs) and field-effect transistors (FETs). Bipolar junction transistors require an input or output current at their control leads. Field-effect transistors practically don’t require currentonly voltage.

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A- Bipolar Junction Transistors (BJTs) Bipolar junction transistors consist of a three-layer sandwich of doped semiconductor materials. We can have two types of bipolar junction transistors: The N-P-N and the P-N-P. Each layer has a pin. On bipolar junction transistors the three pins are labeled: Collector (C), Base (B), Emitter (E). In the photo below, you can see the symbols for NPN and PNP transistor respectively.

NPN Transistor

PNP Transistor

The letter „Q‟ is used to label transistors in a schematic and motherboard How the Transistor Works When a little bit of current flows from the base of a transistor to the emitter, the transistor “closes the switch” so that current can also flow from the collector to the emitter. With no voltage on the transistor’s base, or the controlling pin, no current flows from the base to the emitter. That means no current can flow between the collector and the emitter either. A transistor that allows current to pass is considered on, a transistor that doesn’t allow current to pass is considered off. Apply a small positive electrical to the Base, current will also flow from the Collector to the Emitter.

1- Electrical current flow from the Collector to the Emitter when the Base is on State.

On State

2- Electrical current not flow from the Collector to the Emitter when the Base is off State. Off State

The mechanism of work the transistor NPN

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Apply a small Negative electrical to the Base, current will also flow between the Emitter and the Collector. Off State

1- Electrical current flow from the Emitter to Collector when the Base is on State. 2- Electrical current not flow from the Emitter to the Collector when the Base is off State.

On State

The mechanism x of the transistor NPN

Transistor Testing and Identifying the Leads NPN and PNP transistors fall into the family of bipolar transistors and are easily tested with a multimeter. The transistor is basically and OFF device and must be turned on by applying forward bias to the emitter base junction. Transistors are three-terminal devices that act like two diodes back-to-back. Each junction, like a diode should show low resistance with its forward biased and high resistance when it’sreverses biased. In the following diagram, two diodes are connected together and although the construction of a transistor is more complex, we see the transistor as two diodes when testing it. The bipolar transistor consists of three layers of n-type and p-type semiconductor material arranged either in a npn or pnp configuration.

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Important Note: Transistors come in a variety of case styles. The pin-out for the emitter, base and collector is notthe same from device to device. Likewise, it’s impossible to determine if a transistor is a PNP or NPN type by it’s shape or case design. Everything can be determined using the transistors part number. To get the right pin-out, you will have to refer to a datasheet and look up the device using the part number. Another trick for common, low-power transistors, is to connect the ohmmeter to the collector and emitter, leaving the base hanging open. Apply polarity so the collector will be reverse biased (positive for NPN, negative for PNP.) Now wet a finger and thumb. Hold the base and collector leads in this finger/thumb clamp (don't let them touch). This injects some current into the base. If the ohmmeter resistance reading decreases, the transistor is working. By holding the base and emitter leads between thumb and finger, the resistance should go Up. These simple tests often tell if you have a PNP or NPN transistor, and if it is good or bad. If you have access to a transistor’s data sheet, then you already know a lot about the transistor. You know whether it is NPN or PNP and which lead is the emitter, the base and the collector, However, the transistor's data sheet will show you that.

The first page is usually a summary of the part's function and features.

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Manufacturer Name : FAIRCHILD Transistor type: MMBT2222A Electrode the transistor : NPN Features and characteristics of transistors Physical form (package) of the transistor MMBT2222A is called SOT-23 and another transistor PZT2222A is called SOT-223

Little tip on how to test a transistor Testing NPN transistor like two diodes connected back to back as shown down

Collector Base Emitter 1. Testing between Base and Collector expect high and low on your meter (diode test). 2. Testing between the Base and Emitter expect again high and low on your meter (on diode test). 3. Testing Collector and Emitter expect high both ways. Testing NPN transistor…again use the same principle B) Metal oxide semiconductor field effect transistors (MOSFETs) Another type of transistor is the MOSFET or Metal Oxide Semiconductor Field Effect Transistor is acomponent similar to the BJT in the fact that it can amplify or switch electronic signals. The MOSFET has three terminals or leadsare known as the Gate, Source and Drain. The voltage on the gate terminal controls the conductance of the circuit between the drain and the source. Apply a small positive electrical to the Gate, current will also flow from the Drain to the Source.

1- Electrical current flow from the Drian to the Source when the Gate is on State.

On State

2- Electrical current not flow from the Drain to the Source when the Gate is off State.

Off State

N-Channel MOSFET

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Apply a small positive electrical to the Gate, current will also flow from the Source to the Drain.

1- Electrical current flow from the Source to the Drain when the Gate is on State.

Off State

2- Electrical current not flow from the Source to the Drain when the Gate is off State.

P-Channel MOSFET

On State

Testing MOSFETs You should know that most of the Mosfet has a Flyback diode between source and drain, so that when testing you will get a reading in one direction between source and drain and this is normal.

A Fly back diode inside The Mosfet and negative lead of flyback diode connected with drain lead of Mosfet

N-Channel MOSFET

Fly back diode inside the Mosfet and negative lead of flyback diode connected with source lead of Mosfet

N-Channel MOSFET

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N-channel MOSFET Set to the diode test mode 1- Put the black test lead on the drain pin and put the red test lead on the source pin 2- You should get a voltage reading of between 0.45-0.7

Reverse the test leads

1- The red test lead is on the drain pin and the black test lead is on the source pin 2- You should get an O.L Reading.

Note: If you get a low reading in both directions between source and drain the Mosfet is considered shorted and if you get an O.L reading in both forward and reverse bias directions the Mosfet is considered open.

P-channel MOSFET Testing the P-channel Mosfet transistor is just the same way a show you checked the N-channel Mosfet transistor. Set to the diode test mode 1- The black test lead is on the drain pin and red the test lead is on the source pin 2- You should get an O.L Reading.

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Reverse the test leads 1- Put the red test lead on the drain pin and put the black test lead on the source pin 2- You should get a voltage reading of between 0.45 - 0.7

You should always try and find a datasheet for the MOSFET you are testing, inside the datasheet you can find lots of useful information, let‟s take example how to test Mosfet transistor with help of the datasheet. We will search for the DataSheet for Mosfet transistor model APM2510N. First, read the part number printed on the Mosfet and then go to www.google.com search engine or use a search engine like AllDataSheet.com and write one of these keywords as shown below: APM2510N datasheet APM2510N pdf APM2510N code APM2510N circuit APM2510N marking APM2510N diagram

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Download datasheet file to your computerand open datasheet to know the type the transistor that we want to test it and properties and identify which pin is the drain, gate and the source.

When you read the first page you will find a lot information, type and features and characteristics of the transistor. Manufacturer: ANPEC Transistor model name: APM2510N Transistor type: N-Channel MOSFET Physical form of the transistor (TO-252) and Pin Configuration Definitions G,D,S Transistor Symbol. Features of transistors as voltage rating, maximum current and maximum voltage, these features are described in detail in the table on page 2. 7- Applications: this tell us for what we can used this transistor here the manufacturer used this type in desktop computer and dc/dc converters. 123456-

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Set a multimeter to “Diode mode” and connect the black test lead to pin drain “D” and connect the red test lead to the pin source “S”. working Mosfet will have reading between 0.45-0.7

Reverse the leads so the black lead isconnected to the source “S” and the red lead is connected to the drain “D”. The multimeter should indicate the OL mark. (Over

Limit).

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You should keep in your mind the transistor comes in different physical size, shape, let‟s first get familiar with A Transistor Outline number or TO, some TO numbers are shown here:

DIP-8

DFN SO-8 FL

SOIC-8 or SOP-8

SOT-223

TO-252

TO-251

SOT-23

TO-220 TO-126

Let‟s get example how to test Mosfet transistor with the eight legs (SOIC-8). Example for Mosfet transistor model AO4409: Transistor model AO4409 belong to SOIC-8 package(8 legs). The datasheet for the AO4409 should tell you what each pin does. Try searching online for “AO4409 datasheet”. When you find the datasheet and open it, you should see like this:

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Manufacturer: ALPHA & OMEGA SEMICONDUCTOR Transistor model name: AO4409 Transistor type: PNP Channel Mosfet Short Description Some characteristics of transistor like the voltage Physical form of the transistor (SOIC-8) and Pin Configuration Definitions G,D,S Transistor Symbol Described in detail and features of transistors as voltage rating, maximum current and maximum voltage.

The legs of a transistors are numbered counterclockwise, starting from the top left. The topis indicated by a little notch or circle.

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The photo below identify which legs are the drain, gate and the source.

5

Legs 5, 6, 7 and 8 are Drain legs

4

8 1

Leg number 4 is Gate leg

Legs number 1, 2 and 3 are Source legs

Set a multimeter to “Diode mode” and connect the red test lead to source “S” and connect the black test lead to drain “D” the multimeter should indicate the OL mark.

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Reverse the leads, the black lead is connected to the source “S” and the red lead is connected to the drain “D”, the multimeter should have reading between 0.45-0.7 Test modern Mosfet transistor DFN SO8-FL example for Mosfet transistor model 4935N

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4935N is N-Channel Mosfet so set a multimeter to “Diode mode” and connect the red test lead to leg drain “S” (you can place lead tester on any of three legs because they all the source) and connect the black test lead to the leg source “D” (you can choose any leg 8, 7, 6, 5 because they all drain), The multimeter should have reading between 0.45-0.7

Reverse the leads so the black lead is connected to the source “S” and the red lead is connected to the drain “D”. the multimeter should indicate the OL mark

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Integrated Circuit (IC) Integrated circuits (IC) are a key part of modern electronics. They are the heart and the brain of most circuits. They are small "chips" of black color that can be found on almost all circuit boards. An integrated circuit is a collection of electronic components (resistors, transistors, capacitors, etc.) all embedded within a small chip. They have different functionalities, among which can be found: logic gates of a circuit, operational amplifiers, voltage regulators, microcontrollers, microprocessors... etc. There are many different types of integrated circuits (IC), each of which has unique dimensions, mounting-types, and/or pin-counts.

QFP

SOP-8 or SOIC-8

PLCC-32

QFN

TSSOP-8

SOT-223

BGA

DIP-8

SOIC-32

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All components with PU code are IC, but the code function is different. A lot of PU on the motherboard. So, for beginners, you should creative to take one sample motherboard and see how much PU in the motherboard, then take a look datasheet to know the function and how it works. IC is the brain of each circuit (controller). Let us simplify easily, only if IC for voice then we call IC sound. Identification of a good or bad IC should be with schematic to know the inputs pin and outputs. Measurement techniques must also use voltage not like other components in general.

TPS51125 Dual-Synchronous Step-Down Controller

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The most important integrated circuits are in Laptop Motherboard 1

EEPROM (BIOS)

IC used to store relatively small amounts of data

Limit the flow of electrons, reducing current

2

Super I/O

3

Clock Generator

Resists changes in the electrical current when passing through it

4

Voltage Regulator

Protects the circuit from the risk of increasing electricity current

5

PWM Controlle

Allows the electric current to pass in one direction only

6

Microprocessor

Generates a very precise frequency electrical signal at a specified time

Letter that symbolizes the Integrated circuits (IC) on the motherboard is U and may have another letters PU.

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EEPROM An EEPROM short for (electrically erasable programmable ROM) it is an integrated circuit (IC). In terms of applications, stores information that can only be read. Modifying it is either very difficult, EEPROM is also a type of non-volatile storage, which means that the information is maintained even if the component loses power. In the picture below, is an example of what a EEPROM chip may look like on your laptop motherboard.

It contains the basic instructions for what needs to happen when a laptop is powered on. This is typically referred to as the firmware of a laptop. The firmware represents the basic code to get the laptop started. Firmware is also referred to as BIOS or basic input/output system. The BIOS also includes a test referred to as a POST (Power on Self-Test) which will ensure that the laptop meets requirements to boot up properly. If the laptop does not pass the POST you will receive an error message which may be text on the display screen and/or a series of coded beeps, depending on the nature of the problem. Since POST runs before the laptop's video card is activated, it may not be possible to progress to the display screen. The pattern of beeps may be a variable number of short beeps or a mixture of long and short beeps, depending on what type of BIOS is installed.

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PLCC-32

TSSOP-8

DIP-8

Three Common forms of EEPROM in the laptop motherboard

Some example of (EEPROM) BIOS chip and their location in the laptop motherboard

EEPROM IC (Bios IC) Model TSSOP-8

TSSOP-8 Package

PLCC32 Package

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(Bios) EEPROM IC on the Schematic diagram usually represent by SPI ROM or SPI Flash ROM

BIOS manufacturer Here is a list of popular bios Manufacturers

Company Name MXIC EON AMIC Numonyx SPANSION WINBOND SST ATMEL

Shortcut MX EN A M S W SST AT

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Manufacturer = SST Type = 49LF004B 33-4C-NHE Package design = PLCC-32 (2x7 and 2x9 Pins = 32 Pins)

Manufacturer = WINBOND (stylized "W") Type = 25X80VAIZ Package design = DIP-8 (2x4 Pins = 8 Pins)

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Super I/O Super I/O or super input/output or SIO, it is an integrated circuit on a laptop motherboard. The Super I/O chip controls most of input and output units as parallel ports (printer), power management, keyboard, touch pad, Temperature sensor and fan speed, bios.

Super I/O Production of Company SMSC

Some newer chipsets are combining the Southbridge and Super I/O chips into a single chip and referring to this chip as the Super Southbridge chip. Some manufacturers such as NVIDIA and SiS have even combined the Northbridge, Southbridge and Super I/O into a single chip.

How do I know what IC is the Super I/O on motherboard? Identifying the Super I/O on mothetboard is often easy if you look for an integrated circuit that is labeled with a company's name that manufacturers Super I/O chips. Some common Super I/O manufacturers are Fintek, ITE, National Semiconductor, Nuvoton, SMSC, VIA, and Winbond.

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Clock Generator Every laptop has the “clock generator” to generate clock signals used through out the system. Timing in a laptop system is critical particularly to synchronize the activities within the various chips. To do this, a crystal is used, and this is a picture of a crystal and clock generator. Crystal Oscillator

Clock Generator

The most common crystal is a 14.318 MHz crystal, and one of the reasons that this particular frequency shows and it's because within the world of crystals this is an extremely stable frequency and it serves as the foundation frequency for generating all of the other timing circuits in a PC. This frequency would be multiplied or divided as necessary and we would get the frequencies like 33 MHz for the PCI, 8 for the ISA and 48 MHz for USB.

Crystal Oscillator

Clock Generator

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Voltage Regulator It is an electronic component belongs to integrated circuits (IC), The voltage regulator is simply an electrical device which can sustain the voltage of a power supply within suitable limits. The electrical equipment connected to the voltage source should bear the value of the voltage. So, the source voltage should be in a certain range which is acceptable for the connected equipment. This purpose is fulfilled by implementing a voltage regulator. It regulates the voltage regardless of the alteration in the input voltage or connected load. It works as a shield for protective devices from damage.

Pin Description

Input voltage

Ground

Output voltage Laptops have voltage regulator on the motherboard and its used to output of voltage with low voltage difference than the internal voltage range.

Example: Voltage Regulator Model G2997F6U

Voltage regulator model G2997F6U in the HP G62 laptop

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Input voltage VIN is the IC power supply input voltage

Output voltage used to power chip on DDR memory, this voltage equal VDDQSNS/2 Voltage regulator G2997 Pin Description

Pin 10 is (VIN) voltage input of IC for work, powered by 5V. PIN 1 is (VDDQSNS) input voltage, equal value of DRR3 RAM (1.5V). PIN 3 is (VTT) This pin is used to the voltage regulator output, VTT value It will be equal VDDQSNS/2, here we have 1.5/2 = 0.75v. 0.75v its responsible for supply chips located on RAM.

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Testing voltage regulator Model G2997F6U Set the multimeter to DC mode and first connect the Red test lead to the input pin 10 (VIN) and the Black test lead to ground, the voltage that we should read should be 5v, after that put the Red test lead to the pin 1 (VDDQSNS) and the Black test lead to ground the voltage that we should read should be 1.5v. Now read the output voltage pin 3 (VTT) place the Red test lead of the multimeter on the pin3 and the Black test lead on the ground, we should now read a voltage at or about the rated voltage that the regulator is designed for, here we should get 0.75v.

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PWM Controller Before we talk about PWM, we need to explain the basics about signal types. There are two basic kinds of signal types - Analog and Digital. Analog signal types have degrees of intensity, between 0% (off) and 100% (maximum), allowing for a range of accuracy when determining something like screen brightness or fan speed. Digital signal types, on the other hand, have no degrees of intensity, they simply have an off or on state. This means something like brightness control is impossible on its own, because in digital terms, the backlight is either on or off. Digital signal controllers, however, are cheaper, smaller, more power efficient, and simpler to implement than analog controls. In order to take advantage of the benefits of digital signal controllers while retaining (and even surpassing) analog functionality, PWM is used.

PWM tests at differing levels of brightness ranging from 100% to 0% PWM is a very rapid frequency of on/off states of the digital signal to achieve a result similar to what could be achieved on a plain analog signal. If you wanted 70% screen brightness for example, you would simply need to keep the digital

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signal on for 70% of the time and off for 30% of the time your screen was turned on. This is done rapidly, with the frequency measured in Hertz (Hz), or number of times per second. The faster the frequency, the less noticeable the off states become, until the resulting effect is indistinguishable from what an analog signal would produce. Is PWM necessary? In short, yes. PWM is used not only for LCD monitor brightness, but most forms of finite control in electronic devices today. Servo motors and fan speed control (you may notice that case fans for a computer will sometimes be rated as with PWM) are two common implementations of PWM. New technology such as what is found in smart phones is too small and designed to use too little power to utilize any alternatives such as analog controllers.

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Microprocessor A Microprocessor is an electronic component that is used by a computer to do its work. It is a central processing unit on a single integrated circuit chip containing millions of very small components including transistors, resistors and diodes that work together. One of the most famous IC's belonging to the Microprocessor IC series is the Southbridge, Northbridge and VGA Chip. The northbridge typically handles communications among the CPU, in some cases RAM, and PCI Express (or AGP) video cards, and the southbridge. Some northbridges also contain integrated video controllers, also known as a Graphics and Memory Controller Hub (GMCH) in Intel systems. I/O Controller Hub (ICH) is a family of Intel southbridge microchips used to manage data communications between a CPU and a motherboard, specifically Intel chipsets based on the Intel Hub Architecture. It is designed to be paired with a second support chip known as a northbridge.

In the modern laptop motherboard Northbridge and Southbridge has been integrated into one chip called the Platform Controller Hub (PCH).

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Part 5 Identifying of Common Components of the Laptop Motherboard

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This part will introduce the common electronic component you will find on laptop motherboard.

Capacitors (C): Tantalum Capacitor Polarity Indicator (+) PC157 Location Marking Capacitor Symbol

SMD Electrolytic Capacitor

Polarity Indicator (+)

PC177 Location Marking

PC175 Location Marking

SMD Ceramic Capacitor

Ceramic Capacitor Symbol

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Nec Tokin Capacitor

Capacitance and Working Voltage

Typical Example of Capacitors

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Inductor – Coil (L):

Inductor

Location Marking

Inductor Symbol

Inductor

Capacitor Location Marking

SMD Inductor

Location Marking

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SMD Inductor Inductor Symbol

Typical Example of Inductors

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Fuse (F):

Fuse Location Marking

Fuse Symbol

Ceramic Capacitor

Typical Example of Fuse

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Diode (D): Diode Location Marking

Black line represents Cathode terminal in Diode Diode Symbol

Dual Diode Symbol

Diode with 3 legs (SMD Dual Diode)

Zener Diode (ZD or PD): Zener Symbol

Zener Diode

Black line represents Cathode terminal in Zener Diode

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LED: LED Symbol

LED

Negative side of the LED G = Green color R = Red color

Crystal (X or Y): Crystal Symbol

Crystal

Typical Example Of Crystal

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Resistors (R):

A Resistor

A Resistor Network

A fuse resistor

Resistor value Resistor Symbol

NTC thermistors Symbol

Location Marking

Negative Temperature Coefficient (NTC thermistors) are resistors with a negative temperature coefficient, which means that the resistance decreases with increasing temperature. They are primarily used as resistive temperature sensors and currentlimiting devices.

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Mosfet (Q):

Mosfet 3 legs

Mosfet Symbol

Mosfet 6 legs

Mosfet Symbol

Mosfet 8 legs

Leg Number one

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Transistor (Q): Transistor Symbol

Transistor

Connector: Connector Symbol Connector

Leg Number one

FAN Connector:

FAN Connector

Connector Symbol

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Battery Connector:

Battery Connector

Battery Connector Symbol

Bios: Bios IC

Bios Symbol

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Part 6 Documents Related to the Laptop Motherboard

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The documents related to the laptop motherboard and define each one and whether you need it. 1- User Manual:

A user manual is a document related to the laptop explaining its operation and how to use it, you don't need this document while repairing the motherboard. 2- Service Manual:

A service manual is a document related to the laptop describing all the services provided by the laptop and how to keep in good state, you don't need this document while repairing the motherboard.

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3- Schematic Diagram:

The schematic diagram is the most important document related to the motherboard, it provides a detailed explanation of each Integrated Circuit and its pins and connections, it's your map while repairing the motherboard. 4- Block diagram:

The block diagram is a single page within the schematic diagram document, it contains the connections between the different Integrated Circuits of the motherboard.

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5- Datasheet: The datasheet is not related directly to the laptop motherboard, it's a document related to a single Integrated Circuit in the motherboard, it contains a detailed description about its pins and inputs and outputs and the possible installations and many more.

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Part 7 How to Read DataSheet?

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Unfortunately, these documents are usually written by engineers for other engineers and as such they can often be difficult to read, especially for new comers. Lots of websites that provide document datasheet or component data. For example: www.ti.com www.alldatasheet.com www.alltransistors.com www.electronics.stackexchange.com www.www.datasheetcatalog.com.com When you open datasheet the first page is usually a summary of the part’s function and features. This is where you can quickly find a description of the part's functionality, the basic specifications (numbers that describe what a part needs and can do) and sometimes a functional block diagram that shows the internal functions of the part.

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Pin Configuration A pinout lists the part’s pins, their functions and where they’re physically located on the part for various packages the part might be available in. You'll find some acronyms here: DCIN (pin1) is DC Supply Voltage Input, BATT (pin16) is Battery Voltage Feedback Input, DLO (pin2) is Low-Side Power-MOSFET Driver Output, etc.

Detailed of electrical specifications follow. These will often list the absolute maximum ratings a part can withstand before being damaged. Never exceed these or you'll be replacing a possibly expensive part!

Some parts will have one or more graphs showing the part’s performance vs. various criteria (supply voltage, temperature, etc.) Keep an eye out for "safe zones" where reliable operation is guaranteed:

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Some datasheets will include example schematics for various circuits that can be built around the part. These are often very useful building blocks for interesting projects, so be sure to look through them:

At the end of many datasheets is packaging information, which provides accurate dimensions of the packages a part is available.

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Part 8 Motherboard Part Numbers

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When troubleshooting a laptop motherboard to component level it's mandatory to know the manufacturer or the board as a starting point in search for aide. To be able to locate the schematic this information is mandatory since we can’t go by a laptop's model number for the simple reason that a laptop model number may use different motherboards. So in this part 7 will give you some basic information on how to identify the manufacturer of a motherboard.

What is laptop ODM? “OEM” stands for "Original Equipment Manufacturer" An OEM is a company that manufactures or develops something that is sold by another company. Laptop computer like Apple, LG, Acer, HP, Dell, Lenovo, Fujitsu-Siemens, BenQ and etc., they are not manufacture their laptop motherboard. All of them are using the same Taiwanese OEM (An Original Equipment Manufacturer) and Chinese factories. For example, a Dell laptop might contain an AMD processor and a Samsung SSD. AMD would be the processor OEM and Samsung would be the OEM of the storage device. An iMac might contain an Intel processor and Micron RAM. In this case, Intel and Micron are the respective OEMs. There are about 10 major motherboard manufacturers and everyone of them has its own “hand writing”. The main ones are Quanta, Compal, Pegatron (spun out of Asus), Foxconn (Hon Hai), Wistron (spun out of Acer), Inventec etc. List of some OEM (Original Equipment Manufacturer) Quanta Compal Inventec

BENQ JoyBook S41 DA0CH3MB8E0

Dell Latitude D630 LA-3301P

HP NX6325 6050A2030501MB-A05

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Sony

Asus

Wistron

SONY MBX-123

ASUS EEEPC P701

Wistron JE40 HR – 48IQ01.031

Quanta is probably the biggest laptop manufacturer, followed by Compal and Pegatron. Compal and Pegatron probably have the best quality overall. Information about the manufacturer and motherboard model laptop very important to us. you might need to know model number motherboard’s model for a number of reasons as stated below: 1- Looking for motherboard BIOS file or the need to update the BIOS of motherboard. 2- Looking for a motherboard schematic. 3- Need to update the drivers of hardware as audio drivers.

How to get the schematic diagram? The easiest way to look for the schematic diagram in the internet is by using the laptop reference, for example: Acer Aspire 1300, Hp pavilion DV5-1000us etc. In case you don't find the schematic using the laptop reference you can use the ODM. To look for the motherboard schematic using the ODM method look for a reference printed in the motherboard and use it to search for the schematic, below is an example of those references for ODMs:

Find the motherboard model number This is usually printed on the motherboard, but can be located in several possible locations, for example, it may be printed near the RAM slots, near the CPU socket, or between the PCI slots. There will be a lot of writing on the motherboard, but the model number is usually written in the largest text (Motherboard model numbers are typically a collection of numbers and letters).

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Look for your motherboard schematic online Go to a search engine of your choice (Google) then type in your model number followed by the word "Schematic or Diagram" and press entre. This will bring up a list of matching schematic motherboard models.

Carefully review the search results. Watch in particular for results in PDF format, as most manufacturers that do list their schematics online will do so in PDF (Adobe Acrobat) format.

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Click link to download schematic

Put your schematic to your folders

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Part 9 How to Read Laptop Schematic?

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The most important part of the motherboard repair process is understanding the schematic diagram, you can't do anything without getting that document and understanding it.

What’s the schematic diagram? A schematic diagram, in effect, as a map of an electronic circuit, showing all of the components and how they interconnect with one another. When you troubleshoot a laptop motherboard you need to use the schematic diagram to find the faulty component in relation to other components in the circuit.

Important Part Schematic Diagram Cover Page The cover of the schematic diagram of the laptop as same as the cover of a book. The cover page contains a reference of the laptop and the version of the document, it may contain a table of contents as well, telling you what each page is about.

But if the table of contents is absent it's always possible to find out about each page, note the cover page design is different for each brand.

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Name of Manufacturer

Hardware Instaled Version and date of the document

Code Motherboard

Then comes the block diagram, which describes the connections between different Integrated Circuits of the motherboard, you find the number of the page that discuss every IC listed there, so it's another way of a table of contents. Then in the next page come sometimes some descriptions of the voltages mentioned in the document and sometimes the states in which they are present, as well as some other general useful information.

Voltage Description

Other Information

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Then generally come the description of every integrated circuit in the motherboard and every slot or port including the power button and the battery connector. Then comes the description of each IC with all its pins and connections, if you want a more detailed description to know exactly what are the IC's inputs and outputs and everything you should download its datasheet. After that comes the description of the motherboard circuits like the charger circuit or the different voltage generator circuits, note that a circuit is a network of electronic components that perform a specific task.

Charger circuit Knowing what each page is about is essential to understand the schematic diagram document, as we said earlier you can refer to the table of contents or looking at the bottom right of the page gives a description of the page.

Page Description

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Understanding Basic of Schematic These tips will be based on the schematic of Compal LA-4101P motherboard. On the other hand understanding a schematic diagram is the ability to understand how the circuit described works, you have to be able to read the schematic diagram first and be familiar with electronic components and their functions and how they operate, this is what you really need to know, and it comes with practice and experience, we will explain some circuits in this training to give you an idea on how to decipher them. Let's get more on how to read schematics: Laptop schematic have on their front pages a block diagram is intended to provide information of all board components, in brief. In him we have a lot of information: - Socket processor used. - If the board uses PCH or set North Bridge / South Bridge. - Bios used (we can also see if the card uses one or two bios). - The code of the main components. - In some schematic, we still have the page information in which the circuit is. If this item is not part of the schematic, you have to manually fetch the page that contains the circuits that we need to analyze. This can be seen on page 2 of our schematic. Note that in this schematic we have an indication of the page where the matching circuit is. For example, if we need to analyze network circuit (LAN), we directly to page 30 of schematic.

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Schematic Path and Connection Between Circuits Schematic symbol for conductors that cross paths but are not electrically connected. Not Connected

A path that only passes and does not have a relationship. And in principle the line is a path connecting one components and others that connect one pin and others.

Schematic symbol indicating conductors that intersect electrically. Every time there is a point in the intermediate meeting both wires indicate the existence are patronship or a triangle path or branch line or path junction or cross path. Wires can connect two terminals together or they can connect dozens. When a wire splits into two directions, it creates a junction. We represent junctions on schematics with nodes, little dots placed at the intersection of the wires.

Connected

It is evident that you cannot show all the connections of the components on a single page, and for this reason, the schematic is always divided into several pages.

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To show the connections from one circuit to another, schematics manufacturers have adopted symbols to indicate the types of input signals, output signals and bidirectional signals (input and output on the same terminal).

Another rule is quite adopted in relation to the names of the signs, as can be seen below. 2

1

3

On the inside of the component (1), we see that the terminal has the name given by the component manufacturer and can also be found in its datasheet. The name displayed outside the component, with the signal line (2) is the name given by the schematic from the manufacturer. Note that next to the signal name appears a number (3). This is the page number which is the continuation of this circuit, i.e. the circuit where this line will be connected. We see in the image below where these signs come together.

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That is, the signal R_CLKREQ # _9 generated in U44 and on page 25 is the diagram, is connected to pin 43 of the clock generator, which is on page 17 of the schematic. This page statement where there is a continuation of the circuit is practical, but the best method is to use the search the PDF reader, where we can find all the points at which this signal is on. Simply enter the signal name in the search and perform the search. In the case of circuits of the power supply (supplies) the schematic usually shows a terminal named voltage.

In the image above, we see the voltages +3VALW and +3V_LAN. Note that the voltage +3VALW Mosfet is the input voltage and the voltage +3V_LAN It is the output voltage. See also in this case, the drain of Q106 is the point of the voltage source +3V_LAN. This is where this voltage is generated. Although the two voltages have the same value (+3V) after passing through the Mosfet the signal name is another, this is very common in any electrical schematic.

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Below is another example of the change of names of the signalsor voltages after passing through certain component.

This is important when we are reviewing the schematic and need to know where certain voltage is generated. That is, when we have a missing voltage on the motherboard and we need to find the source of this voltage in the diagram. Another important detail are the symbols shown next to the component references.

The image above, we see that the capacitor C357 has the @ (At) symbol next to your reference. This indicates that the capacitor isoptional and will depend on the card manufacturer if this component will be mounted on the board or not. We can find some variants of this symbol as an asterisk (*) registration OPTION and others. The important thing should always keep in mind that if any component has a symbol next to their reference in the schematic, it is optional and cannot exist on the motherboard. See an example below:

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Information The wiring diagram may also contain various information that can help us in the repair of the motherboard. An example is shown below. Page N° 4

Here we can see the connection of the motherboard of sources and we will make some considerations about them. For example, enrollment B.C the next block VIN, indicates the motherboard power entry mode charger. We see that this point is connected to block B+ this block is generated and other stresses. For example, let's admit that we do not have the voltage +3VALW on the motherboard. We see the picture above this voltage is voltage dependent B++ that is the source voltage +3VALW. So, we already have a starting point to begin the analysis of the defect. Of course, the generating circuit voltage +3VALW depends onother factors to work, but we already know that the line B++ It is critical to its operation. Another important information that this schematic gives us is the sequence in which the signals appear on the motherboard. See the image below. In it we have the inscription AC MODE, indicating that this table is only valid for the mode charger. If you had the inscription DC MODE (or something) would be just to battery mode.

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Note that in this case, the signs left follow a descending order. In this sequence other schematic can be shown from bottom to top. To identify the order in which these signals are, simply identify the VIN signal, which is usually always the first signal to be generated on the motherboard. In some schematic, it may have another name. From it, we head to the other, which may be above or below this sign. In the case of the image above, we see that the VIN signal is first on the list and in this case the sequence is decreasing. Note that the VIN signal is immediately in front of a waveform showing how this signal behaves. Note that the initial part of the stroke begins on the bottom line and at one point, it rises to the top line. The bottom line is the 0V voltage while the top line represents the maximum voltage according to the signal. Following the waveform VIN, we see that the voltage starts at the bottom row (0V) and connect the charger changes its value to the upper thread (maximum value, which is typically 19V) and remains so until the boot is removed. After the voltage VIN reaches its nominal value, the next voltage for operation is B+. Following the same principle. Note that it remains at a low level (0V) to the voltage VIN is stabilized (note that the point at which it rises to the top row is different from the waveform VIN). Watching from left to right, see how the B + "Delay" a little more to reach its maximum voltage. This sequence occurs automatically in all signs, one after the other until the signal ON / OFF # (Power button).

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From this point the sequence is interrupted and the card is waiting for the user presses the power button. This is the condition of Stand-by the board. Note that the form of signal wave ON / OFF # It is inverted relative to the other. It starts on the top line, after a time down to the bottom line, remains at this level for some time and again rises to the top line.This tells us that the power button in normal state, begins its work cycle at a high level (typically 3V) and be tight, is low (0V) while the button is pressed and returns to the high level after the button it is released. In short, after connecting the charger, the adapter initiates some signals (voltages) and enters a standby state. To repair the board, wehave to check if all these points have the corresponding voltages. It is clear that if one of them missing, the card will not turn on. After the standby voltages are at normal levels, when pressing the power button, other voltages arise, according to the sequence shownin the above figure and can be seen on page 5 of schematic that we are using for this example.

Finding signs To search for these signals in the schematic, again we count on the help of our search PDF reader. For example, if we need to find out where the signal (voltage) VIN, do a search for the schematic with that information. In the case of this schematic, we will find many points where this signal is present, but to facilitate the measurements on the motherboard, choose alocation easily accessible, as shown in the image below. In this case, we chose the drain PQ101, since it is relatively easy to find component on the motherboard.

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Confirmed that our first signal is present, we can seek other points, following the sequence shown above start. Thus, we can identify where the voltage ceases to exist and this is where we must begin the analysis. The search system is also interesting when we need to locate a specific component that we have on board and want to know about the circuit to which it belongs. Unfortunately, not all schematic brings such detailed information about the schematic we are using. Other schematic may contain variations of such information, as they are not fixed rules to all manufacturers.

Related Search We know that the card input circuit (usually VIN) is made in the charger circuit and this circuit exchange some information with the SIO. Thus, the SIO identifies that there is a connected charger and sends an acknowledgment signal to the motherboard connect. This exchange of information between the circuits is very common in any motherboard. Often, this "permission" to call the motherboard is sent by the SIO to the PWM generator circuit of the 3.3V and 5V, as we shall see. This varies from project to project but the method described below can be applied to any schematic and thus is easy to identify these points. The first step is to identify the page number where are the circuits that we analyze. In the schematic we are following, we can seeon page 2 in the diagram motherboard blocks. As we have seen, there have indications of the pages where each circuit or component on the motherboard is important. In this case, the SIO is in page 38. The charger circuit is not identified, but generally will be in the following pages to the DC circuit/diagram of the DC block.

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As the DC/DC circuit is on page 41, our charger circuit should be a page next to it. In this case, it is in page 44 schematic. Thus, we identified that the SIO is in page 40 and the charger is in page 44 schematic. We also saw that each signal that leaves or enters the components, generally have the indication of the page where the circuit goes.

So, we open the diagram on page 44 (charger) and in the search field of the PDF reader we type the page number that is the SIO (40). What we will do is to search the current page related to that we intend to compare.

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The search system will indicate all circuit pin charger related to the SIO which is on page 40 of the schedule. i.e. all pins are connected tothe SIO and the charger. See the image below (use the zoom control of your PDF reader to view better).

According to the symbol in the component terminal, we know if this terminal sends or receives SIO information. This procedure can be used anywhere in the wiring diagram. The same can be done with the page you are on the SIO. In this case, we open the diagram on page 40 and type in the search field. in the page number that is the charger circuit (44) and the searched terminals are connected together.

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As mentioned above, sometimes the SIO sends a signal to the operation of the sources of 3.3V and 5V. This circuit is on page 44 of our schematic. Being in this schematic page and searching for the number 38, we see that two signals have direct communication with the SIO.

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Using this system, we understand how these signals are communicated and thus how the circuit works. The search system is also useful when we are analyzing part of a circuit and need to know where some signal or voltage is generated. For example, analyzing the page circuit 44 we will admit that the voltage VL does not exist. We need to know where it is generated to identify the responsible circuit and verify because it is not being generated.

To find this tension, you type its name in the search field and we all locations where this tension should be present. In this case, we can see that it goes through several components, including PJP301 jumper shown below.

Note that at this point the voltage +3VL gets its name +3VLP. Searching for +3VLP, we found that this voltage is generated at pin 8 PU301. It remains now to analyze why it is not being generated.

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As we were sourcing voltage +3VL it is clear that we were searching in the opposite direction to the schematic and not in the order in which it is generated and feeds the circuit remaining. After locate the signal source, we see that in fact, the voltage +3VLP that is generated in PU301 and after going through PJP301 jumper is what is called +3VL.

How to deal with schematics that don't have the power sequence I'll give you the things that you need to consider in order to make sure that power sequence took place properly. The way to deal with a schematic that doesn't have the power sequence described is to define the necessary things required for the motherboard to boot, those things are: 1- The 5V ALW and 3.3V ALW that are used to power many important ICs such as I/O controller, so the first thing to check is the presence of those voltages, and of course we look at those voltages from where they are generated: the 5V and 3.3V generator.

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Below is an example of 5V and 3.3V generator of a HP Compaq la-1701:

As you can see, we should look for the IC with the reference PU4 and test the 5V in the pin 13 and 3.3V in the pin 2. 2- The next thing we should check is the signal that confirms the I/O controller and the BIOS are ok, as we said in the previous article this signal should be sent from the I/O controller to the ICH, so even if the name isn't the same as KBC_RSMRST you can still look for an outgoing signal from the I/O to the ICH, in the case of the HP Compaq la-1701 the signal name is: PM_RSMRST and you should test it at the pin 3 of the I/O controller:

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3- Then we need to find the signals that confirms the ICH is functional, we know that ICH sends those signals to the I/O controller in the case of the HP compaq la_1701 those signals hold the same name SLP_S3 and SLP_S4:

4- Now we should make sure that the RAM got its voltage and we should look for a signal from the I/O controller to the RAM voltage generator, in the case of the HP Compaq la-1701 the page describing the RAM voltage generator is 38 so we should look for a signal going from I/O controller to page 38 which is SYSON pin 148 of the I/O. 5- The next step is to make sure the CPU got its voltage and we should look for a signal from the I/O controller to the CPU voltage generator, in the case of the HP Compaq la-1701 the page describing the CPU voltage generator is 41 so we should look for a signal going from I/O controller to page 41 which is VR_ON pin 155 of the I/O.

Then concerning the MCH there is two parts of it: The first part is the connection with the CPU we should look for a signal H_CPURST, we test this signal in the CPU slot after removing the CPU, in the case of the HP Compaq la-1701 this signal should be tested in B11 point of the CPU slot:

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And finally check for DDR_CKE0 and DDR_CKE1 and DDR_SRAS# and DDR_SCAS# in the RAM slots to make sure the RAM part of the MCH is functional. This way you made sure all the principal ICs of the motherboard are functional and you have the voltages necessary for the motherboard to function.

Keep reading You’ll find lots of schematics on the Internet. Get a few and practice reading them, focusing on signal flow and organization. Try to deduce which components are generating or passing signals, and which are support systems for the central players. Look for coupling components, filter and bypass capacitors, power supply sections, digital control systems, voltage regulators, oscillators and so on. After a while, reading a schematic will be as familiar as reading a book. You’ll be able to take one look and recognize the sections and stages.

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Part 10 Signal

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Explanation of common signal names about some known manufacturers Now I expect that you already know how to reading schematics I will try to explain the most important signal names used on the motherboard. When a laptop motherboard working, it will send and receives different data and commands to control the circuits. So, the signal is very important for a laptop motherboard to working properly. Like you can notice, when reading different motherboards schematics, each manufacturer uses different signal names.

Signals The arrows of signals symbols given on the schematics randomly, this is because the direction of the flow of the signals can be on both ways. Output signal Input signal

Input & Output signal

The Power good signal CPUPWRGD = The power good signal PG (POWERGOOD) is used to describe that all the voltages supplied to the chip in question are OK at the moment. The PG is usually high when it is active. For example, after the CPU gets all the voltage that it needs, then the CPU power supply chip will send the PG signal.

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The common abbreviations of PG signal are among others:

PD VTTPWRGD

PWRGDx CPUPWRGD

POKx POK

PWRG SPOK

Example: After RT8205 gets all the needed voltages, then it will send SPOK like you see on the next picture.

Some common Wistron signal names used around the charger chip MAX8725. AD+: The first voltage that the adapter converts. DCBATOUT: Common point of the 19V. ACOK: The adapter detection output for charging chip. DCIN: Power supply input for charging chip. ACIN: Adapter detection input for charging chip. Check next picture.

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The open signal To let a chip work, we need what we call a trigger signal or an open signal. By some chip this is called EN (ENABLE). Written like the way you see it means it is active when it is high. And it triggers the chip to run with a high-level value. By another chip this open signal is given by a SHDN# (SHUTDOWN). the post-fix "#" represents that the signal is active when it is in its low-level state. This means that the signal is closed when it is low. If you want to open it, it must be turned to its high-level state. The combination of the name and the sign "#" emphasis the meaning of that signals whether it trigger/stop the chip with its low value/high value. Check picture

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Reset Signal Reset Signal (RST) means literally: a new signal. When the signal starts, it will reset automatically and jump from low level value to high level value. But during a normal operation, a reset occurs by pressing the reset button, the signal jumps from a high-level value to a low-level value then to high level value. For example: for PCI the signal from 3.3V jumps to 0V, then to 3V, which is a normal reset Jump. Reset signal is generally expressed as ***RST# prefixed with different names such as: PCIRST#, CPURST#, IDERST# and so on. The reset during a small time will have a low-level value. When the motherboard works normally, the reset has a high-level value. Usually we call it a NOT Reset. This refers to the high voltage that Reset has at that moment, the measurement point voltage of the reset signal is 0V. Example: 3.3V platform reset from the South Bridge, after dividing into 1.1V as the CPU reset, shown in next figure.

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+5VALW +3VALW signal This signal used to control many IC's. Those voltages are always present directly when the adapter is plugged or the battery is present. By some new motherboard only +3VALW is present first after plugging the adapter. The +5VALW will be generated after pressing the power button.

PWR_S5_EN PWR_S5_EN is a signal that enables the 5V_S5_PWR/3D3V_PWR_S5 on the MAX8734A.

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+3VL is the 3.3V linear power supply comes from the SMPS, in this case the TPS51125 after pressing the power button, meant to supply the EC and many other IC’s.

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KBC_PWR_BTN# is a signal produced when the power button is pressed and sent the EC. This signal is one of the signals that allow the EC to be triggered.

Clock signal The clock signal, noted on schematics as CLK (CLOCK), is a signal that provides a way of comparison (benchmark) between the works of different digital circuit, so that each connected device delivers a unified work and the basic unit of the clock is Hz (hertz). On the motherboard we find a main clock circuit. The function of this circuit is to provide a suitable clock frequency to all the devices present on this motherboard. This main clock circuit will send different frequency to all the different devices present on the same motherboard, such as: -

CPU is more than 100MHz PCI devices are 33MHz PCI-E device is 100MHz USB controller (internal integrated in the South Bridge) is 48MHz

Chip select signal Chip select (CS) is the name of a control line in digital electronics used to select one (or a set) of chips out of several connected to the same computer bus. If one chip on the same bus needs to use the bus the signal CS will mention the address of that chip.

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Chip select signal is common in BIOS chip, noted as CS# and # means that it is active when it is low. It's sent by CPU from the North Bridge to the South Bridge & finally to the BIOS. It exists or not, which can initially judge whether the North & South Bridge and CPU work and whether BIOS information is destroyed/corrupted. SPI BIOS pin shown in next image, CS# is the BIOS chip select signal.

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Part 11 The Architecture of the Laptop Motherboard

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Power supply and signal On motherboard, on some places we can find a 5V we can call this a 5V power supply. But on other place we can also find the same 5V voltage, but we call this a signal voltage. What is the difference between the voltage power supply and the voltage signal? You can draw quite a lot of current from a voltage power supply (limits depend on the specific power source you are using) and there is no drop-in voltage. Signal voltage, on the other hand, need to be conditioned before you draw any current from them otherwise, they drop in voltage. Most signal sources are capable of only a few milli-watts of power. An important thing that need be taken in consideration in the CLOCK questions is that the connected devices must have the suitable voltage, thus powered on, and need to have the same clock frequency if to be able to communicate with each other. For example: Memory and North Bridge need to have the same clock, after being powered on, to be able to understand and transmit signals between each other. Means after that the main board is powered on and the clock generator circuit is working properly, then afterwards we can measure the clock signal and not otherwise. If the motherboard is not powered on, clock signal cannot be measured. We can use the oscilloscope to measure the clock signal. On the next picture we can see the clock signal of a clock chip benchmark-14MHz

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On the new Intel architecture of single bridge there is nothing new concerning the display signal output. Usually the display signal output will not output by itself. But it will be transmitted to the PCH through the FDI bus, and then the completion of the display signal will be done by the PCH self. This process is different from the AMD single architecture like we will see on the next posts.

The AMD single bridge architecture (A70) After the development of the AMD chipset A45, the mobile version A50, the architecture is changed to single bridge called FCH. There is alot of similarities with Intel single bridge. The bridge and the EC manage almost the same devices as Intel single bridge. The CPU of the AMD also integrates the graphic chip. This gets the name APU. But it can output the display signals directly not like Intel that need to do that through the PCH.

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The Nvidia architecture double bridge (C51M) Nvidia is very famous as a big producer of graphic chips and chipset in laptops and desktops. But at the moment they stopped the production of desktop chipsets. We can find many single bridge chipsets as double bridge chipset in desktops Nvidia architecture on the market. But in the laptop Nvidia architecture mostly double bridge chipsets are present. On the AMD double bridge architecture, we need to mention that the BIOS has a variety of buss connections: 1- Some of them work through X-BUS under the EC chip. 2- Some work through the LPC bus connected in parallel with the EC. 3- And some work through the SPI bus connected to the SB independently.

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The AMD SB (South Bridge) has also allot of similarities as the Intel SB. The SB controls the next devices: 1- Audio chip 2- USB 3- SATA 4- EC 5- etc...

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Under the EC chip the devices controlled by the EC remains unchanged.

High-level and low-level signals In the digital logic circuit, the low-level signal is represented by 0 and the high-level signal is represented by 1. The value of high and low level in the circuit is determined by the circuit and is not limited to a certain value. But in general, 0V is considered as low logic value. And 3.3 is considered as high logic value.

In Apple circuit diagrams the power supply begins in general with PP and does not have any special symbol to be given with on schematics. See the example given on the next photo of the PP18V5_S3.

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The GND or the ground is used to close the circuit power loop. Because without GND no current will flow through the device in question. The symbols used for the ground are VSS or GND.

The North bridge and South Bridge are connected by the so-called Hub-Link that later is named to DMI (Direct Media Interface). The speed of this connection is very fast. The South Bridge controls mainly the next devices: 1- USB devices like camera, blue tooth and card readers etc. 2- Audio card. Modem and audio are on the same line. 3- SATA: Hard disk and CD-ROM/DVD-ROM. 4- IDE: early hard disk and CD-ROM/DVD-ROM. 5- PCI-E device: Network card and card reader, expansion card, mini PCI-E slot etc. 6- EC which is connected by LPC (low pin count got his name because it is one of the busses that has small number pin-out).

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The second architecture of Intel is the single bridge, this begins from HM55 and above. After the Intel chipset 5 series, Intel develops what it calls the PCH (Platform Controller Hub). In this single bridge architecture, you will find the Northbridge integrated in the CPU. If the graphic chip is not discrete it can be also integrated within the CPU. The CPU main's control is: 1- Memory. 2- PCI-E 16X discrete graphics chip. The CPU and PCH Bridge are connected with 2 busses: 1- FDI (Flexible Display Interface) bus. 2- DMI (Direct Media Interface) bus.

In the intel single bridge, the PCH controls almost the same devices as on the bridge architecture among others: 1- USB 2- PCI-E 1X 3- SATA 4- Audio And the connection between the PCH and the EC is still using the LPC bus. And devices under the EC remain unchanged.

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The architecture of Nvidia single bridge (MCP67). In the architecture of the Nvidia single bridge the CPU manages only the memory. The bridge manages all other devices. Because of this the bridge generates all of heat which is a reason that makes the ball of the chip get loose easily and need to be reballing very often.

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In the intel double bridge GM/PM45 architecture, the CPU and the Northbridge are connected through the FSB (Front Side Bus). The Northbridge controls the Memory, PCI-E 16X discrete graphic card and display output interfaces.

The devices controlled by the EC (embedded controller) among others are: 1- Keyboard 2- touchpad 3- BIOS 4- etc. Part of the motherboard BIOS and EC may be connected to the South bridge by the same LPC bus or by a separated bus called SPI.

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The AMD architecture double bridge has some differences from the Intel architecture. Because AMD CPU has a 638-pin it can manage to control the memory directly. But in Intel this is controlled by the GMCH (NB). The NB in the AMD architecture controls all the PCI-E devices where this is done on Intel architecture by the ICH (south bridge). The NB also can integrate the Graphic chip as on Intel architecture and is responsible to output the display signal directly.

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At this moment the chipset used by the main stream laptop on the market are dominated by two manufacturers: INTEL and AMD. Once Nvidia has left the market since 2010, you will find very few on the market the notebook computer products with Nvidia chipset. The CPU used in the architecture of Nvidia double bridge, is the AMD 638. Like in the AMD architecture the CPU can manage the memory directly. The North Bridge is responsible to manage all PCI-E device and output the display signal if the graphic chip is integrated, like the way it is in AMD double bridge architecture. Devices managed by South Bridge and EC does not differ a lot from AMD double bridge also.

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The power supply provides the devices with power and it can have different symbol and names in the schematics. We have for example: VCC, VDD, VCC3, VDDQ, VTT, VBAT, 5VALW, +3VO etc.

- Pulse jumping from high level to a low level is called the falling edge signal pulse. - Pulse jumping from low level to a high level is called rising signal pulse. - And pulse jumping from high to low then jumps to high is called high-low-high pulse.

The rising edge waveform

The falling edge waveform

The high-low-high waveform

KBC_PWR_BTN# is a signal produced when the power button is pressed and sent to the EC/KBC/SIO to be triggered.

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AD_IN# and AC_IN# are signals that let the EC know that the adapter is detected.

LID_CLOSE# means that the lid cover of the laptop is closed. It is active when it is in its low state. If it is active the laptop will not power on. LOGICAL This signal comes also from as you see from the 3V3V_AUX_S3 and 3V3_KBC_S5. Those signals can never be generated if the cover lid is closed.

CLK_EN# after CPU power supply has been are present. This signal will be sent with its low-level state to the Q13 in this case, to let know that there is no problem with the MAX8736 and that CK_PWRGD and VRMPWRGD may proceed to enable the clock generator circuitry.

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CK_PWRGD and VRMPWRGD on the drain of Q13 will be grounded if CLK_EN# is high and the motherboard will never come ON.

CK_PWRGD: After the South Bridge receives the signal VRMPWRGD, the CK_PWRGD will be sent with its high-level value toe the Clock generator to open the clock.

The last signal on the wistron architecture will be the G792_RST#. From this temperature IC this signal will be generated if all the temperature on the motherboard is OK. This signal alerts if the temperature is NORMAL or not. And will generate a high value if the temperature has been seen as a normal one.

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Check the picture. If the signal will be low the NAND GATE U43D the PM_PWROK will get a low value for this will shut down the system.

After a while of searching in different Quanta schematics concerning the linear power supply of 3V and 5V, namely noted as VL, 3V_AL and/or 5V_AL, I found out the next situation: Motherboards: HP, DELL, Packard Bell, Acer, Lenovo and IBM that I have checked are not using the same naming convention for the linear power supply as shown above even using the same Quanta Architecture, but some of them use only VL, others uses both 3V_AL and 5V_AL, and other only 3V_AL. We will give a print screen of a HP Compaq 6320 as an example here bellow.

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One of the great difficulties in interpreting schematics is as follow the signs. In an schematic we have various input and output signals for interconnection of components. It is also true that we have some schematics that hinder the location of components and signals. But with the tips shown, we believe it will facilitate research of these signs, and thus increase the understanding of how the motherboard works.

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Part 12 The Basic Knowledge You Must Know Before Starting to Repair Laptop

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What is a short circuit? - A short circuit is when a voltage or signal is stopped before it makes it to its final destination, short referring to its trip being “Shorter” than it should have been. - A short can be caused by poor soldering that bridges two points together or a failed component that is tying two signals/power lines together that should not be tied together. - A “short to ground” is when a pathway to ground exists that should not.

Red line signifies path of electricity, going to system

Example of a short to ground. - Red line signifies path of electricity. - PC41 went bad and is acting as a wire. - Circuit ends there is a “short” before power can flow “TO SYSTEM”

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Finding a short: Here we have four capacitors on this line. The line works great!

Until one day, water is spilled and a capacitor explodes. PC51 is now sending all the voltage to ground!

Measure each capacitor, right? - Many will turn their multimeter to capacitance or resistance mode and measure PC51 is the bad capacitor. Let’s assume PC55, PC54 and PC50 are working in perfect condition. - We take the multimeter and place black probe on pin 1 of PC55 and red probe each capacitor. This will not work! Can you guess why? - be on pin 2 of PC55.

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- The meter measures resistance by sending out a voltage and measuring what comes back on the other end. - Since all of these capacitors are on the same line, you will get the same measurement reading any capacitor. - PC54 is providing the line a path to ground. - Since PC55, PC51, PC50 all share a line with the bad PC54, they will all measure the same if they are still soldered onto the motherboard. We can use heat for short detection. - Whichever component is warmer is likely the component that is short circuited. - We can use freeze spray to help us detect the shorted component - wherever it evaporates first is warmest. - We can also put alcohol on the board which is cheaper, and evaporates quickly. - Note a perfect short circuit will pass a lot of current but will cause no voltage drop across the short and will not get hot. - An open circuit component will pass no current but will have a voltage drop across it but will not get hot. - A partial short as a result of for example a capacitor failing and passing some dc current will get hotter than normal because it will have a current flowing and a voltage drop across it resulting in a power loss in the component and the component will get hotter than normal.

What is a voltage divider? A voltage divider is a simple circuit which turns a large voltage into a smaller one. - A voltage divider steps down a higher voltage to a lower voltage. - A voltage divider is a series of resistors between a higher voltage and ground. - A voltage divider is inefficient, but cheap used for things that do not have high current requirements.

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Here we have a resistor between a high voltage source and the intended destination, then another resistor between the intended destination and ground. It is turning 12v into 3v. Resistance of resistors will set the voltage. - Allows the enable pin of this backlight IC to get 3v whenever PPBUS_SW_LCDBKLT_PWR is on. - If you sent 12v to the enable pin of backlight IC, it would die. Good thing we have a voltage divider. Used a transistor to control the voltage divider.

What if we used a transistor to control the voltage divider's path to ground? - We could then control whether the voltage divider works. - By being able to control that voltage divider, we can then control backlight being on or off based on signals from other parts of the machine.

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12V

S

This voltage divider is now working as a voltage divider since it has a path to ground

3V

3V

D 12V G 5V This P-Channel mosfet is letting power through since Gate voltage is below source voltage This N-Channel mosfet is letting power through since Gate voltage is above Source voltage

What are System Power STATES? S0 = Computer is on and working. The system is fully usable. Hardware components that are not in use can save power by entering a lower power state. S1, S2, S3 = Computer is sleeping. The system appears to be off. Power consumed in these states (S1-S3) is less than S0 and more than S4, S3 consumes less power than S2 and S2 consumes less power than S1. Systems typically support one of these three states, not all three. In these states (S1-S3) volatile memory is kept refreshed to maintain the system state. Some components remain powered so the computer can wake from input from the keyboard, LAN or a USB device. Hybrid sleep used on desktops, is where a system uses a hibernation file with S1S3. The hibernation file saves the system state in case the system loses power while in sleep. S4 = Computer is hibernating. The system appears to be off. Power consumption is reduced to the lowest level. The system saves the contents of volatile memory to a hibernation file to preserve system state. Some components remain powered so the computer can wake from input from the keyboard, LAN or a USB device. The working context can be restored if it is stored on nonvolatile media. Fast startup is where the user is logged off before the hibernation file is created.

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This allows for a smaller hibernation file, more appropriate for systems with less storage capabilities. S5 = Computer is off. The system appears to be off. This state is comprised of a full shutdown. G3 = Mechanical Off. The system is completely off and consumes no power. The system returns to the working state only after a full reboot. Different power will be present during different states. You need CPU Vcore during S0 while it is on, but you do not want it when it is off – S5. PP5V_S3 and PP5V_S0 are created by the exact same circuit, but PP5V_S0 is only meant to be present when the laptop is on, opened up, and being used.

What is a DC to DC boost circuit? A laptop LCD backlight runs off of about 39 volts in an A1286 MacBook Pro. Its Battery is a 12.6 volt battery. Does this mean we carry around flashlights? No! We boost it. - A DC to DC boost circuit boosts a lower DC voltage into a higher DC voltage. - Think of it like stopping short in a car. - For that split second when the brakes are slammed, you aremoving forward faster than the speed of the car. Good thing wehave seatbelts! - Same concept is applied in electronics. DC to DC boost circuit contains four main elements. - Inductor, this is what we are shorting to ground to create the higher voltage. - Diode, this keeps the boosted voltage from flowing back through the circuit. - Capacitor, this stores the boosted voltage, and also smoothest it into a straight line. - LED driver, this is what does the switching to switch the inductor's output to ground.

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What is a feedback? - These chips are cheap crap connected to other cheap crap. - They are not to be trusted. - Most power control chips in buck converters, DC to DC boost circuits, and power supplies in general like to know what they are doing. For this, feedback is used. - Chip will change how it controls circuit based on feedback. Example:

This is Feedback

FB = Feedback

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Diagnostic method for laptop power supply circuit failure The motherboard power supply circuit of the laptop computer is an indispensable part of the laptop and its problems usually lead to various failure phenomena such as failure to boot, automatic restart, and crash etc. To learn the diagnosis and elimination of the fault of the power supply circuit of the laptop motherboard: Firstly, the basic working principle should be mastered. Secondly, the common fault phenomena caused by the problem of the power supply circuit of the motherboard should be understood. Finally, the maintenance experience of the power supply circuit of the motherboard should be continuously summarized and learned. method. 1- Laptop motherboard power supply circuit basics There are two ways to supply power to the laptop motherboard. One is the dedicated rechargeable battery for laptop computers and the other is to convert 220V mains to 19,5 or 20 volts. Powered by the power adapter. The laptop's dedicated rechargeable battery typically provides a lower supply voltage than the power adapter's input supply voltage. Whether it is a dedicated rechargeable battery or a power adapter for a laptop computer, the power input to the laptop's motherboard cannot be directly used by all chips, circuits, and hardware devices. This is because the functional modules and hardware devices on the laptop motherboard. The current and voltage requirements are different and must be converted after the corresponding power supply. Therefore, various power conversion circuits on the laptop motherboard have become an indispensable part of the laptop computer. At the same time, after the problem occurs in the power supply circuit of the laptop computer, it will lead to various failure phenomena such as failure to boot, automatic restart, and crash. To learn the diagnosis and troubleshooting methods for the power supply circuit of the laptop motherboard, you must first master the working principle and common fault phenomena, so that the fault analysis can be reasonable and the troubleshooting can be quickly and accurately performed during the maintenance of the laptop.

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1- Laptop motherboard power supply The power supply conversion circuit on the laptop motherboard mainly adopts two kinds of switching power supply and linear regulated power supply. The switching power supply is the most widely used power conversion circuit in laptop motherboards. Switching power supply is widely used in the system power supply circuit, CPU power supply circuit, chipset power supply circuit and memory and graphics power supply circuit on the laptop motherboard. The switching power supply uses modern electronic technology to control the "on" and "off" of the electronic switching device (such as the FET) through the power control chip to send control signals to pulse-modulate the input power, thereby realizing power conversion and automatic stabilization. The function of voltage and output adjustable voltage. The switching regulator power supply circuit applied on the laptop motherboard is usually composed of electronic components such as a power control chip, a field effect transistor, a filter capacitor, a storage inductor and a resistor. The power control chip is a power supply voltage conversion control component in the switching power supply circuit and the field effect transistor and the energy storage inductor are voltage conversion execution components in the circuit, and the capacitor in the circuit mainly plays a filtering role. The linear regulated power supply has the characteristics of low noise, fast response, simple structure, low heat generation, low cost and small size. The linear power supply is widely used in the laptop computer's standby circuit, memory power supply circuit and chipset power supply circuit. Provide one or more power supplies for it. The linear regulated power supply circuit usually consists of a small number of electronic components such as a linear regulator chip, a capacitor and a resistor. When a linear regulated power supply is used to supply a reference voltage in the memory supply circuit, it is usually designed on the motherboard. Near the memory slot when the chipset power supply circuit uses a linear regulated power supply to provide a certain power supply, it is usually designed around the motherboard chipset. 1-1- Protection isolation circuit and charging control circuit 1. Protection isolation circuit Protection the isolation circuit is an important part of the laptop computer power supply circuit. It connects the power adapter and the rechargeable battery to form the external power supply of the two-way notebook motherboard, and chooses to deliver one of the power supplies to the motherboard. Kind of power supply circuit.

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The main function of the protection isolation circuit is to switch the power supply mode of the laptop. The choice is whether to use the power adapter to supply power or a rechargeable battery, and provide certain protection functions. Switching the power supply mode of the laptop means that when the laptop has a power adapter and is powered normally, the protection isolation circuit selects the power adapter to supply power to the motherboard of the laptop. When there is no power adapter power supply or the power adapter is powered abnormally, the protection isolation circuit will choose to be powered by the laptop's rechargeable battery. The protection isolation circuit of a laptop usually consists of electronic components such as a field effect transistor, a resistor, a capacitor, a triode and a charge control chip. The power supply switching function of the protection isolation circuit is mainly realized by the switching function of electronic components such as field effect transistors in the circuit. Electronic components such as field effect transistors have the property of allowing current to pass when conducting, and not allowing current to pass when they are turned off. By utilizing this characteristic of an electronic component having a switching function such as a field effect transistor, and further controlling the charging control chip in the circuit, the power supply switching function of the protection isolation circuit can be realized. In addition to the function of controlling the on and off of electronic components such as FETs, the charge control chip in the protection isolation circuit has the function of monitoring and detecting whether the voltage and current in the circuit are normal. When the external input power supply is abnormal, the protection isolation circuit cuts off the input power supply, thereby protecting the circuit of the latter stage. Different manufacturers and models of laptop, the protection isolation circuit has a certain difference in design, the above is only its basic principle, and in the troubleshooting process of the laptop, should be further analyzed according to the circuit diagram. 2. Charging control circuit The charging control circuit is also an important part of the laptop power supply circuit. Its main function is to convert the input power of the power adapter into the charging power of the rechargeable battery. The core component of the laptop charging control circuit is the charging control chip, which controls the charging process of the rechargeable battery of the laptop.

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The charging control circuit of a laptop usually consists of electronic components such as a charging control chip, a field effect transistor, a capacitor, an inductor, and a resistor, and belongs to a switching regulator power supply circuit. The FET in the charge control circuit receives power from the upper circuit and the charge control chip can control the turn-on and turn-off of the FET in the circuit. The inductor mainly plays the role of energy storage in the circuit. The capacitor mainly functions as a filter in the circuit. After the charging control circuit converts the input power of the power adapter, it outputs the voltage and current required for charging the rechargeable battery of the laptop. At the same time, the charging control chip can also detect and monitor the charging process to prevent damage to the rechargeable battery. Problems with the protection isolation circuit and charging control circuit of the laptop will cause the laptop to fail to boot normally, and the rechargeable battery cannot be charged normally. 3. The circuit analysis Charging control chip is the core of the laptop protection isolation circuit and the battery charging control circuit, and has the functions of detecting and controlling the working process of the whole circuit. The following takes the ISL6251 charging control chip as an example to elaborate the basic working principle of the laptop protection isolation circuit and the charging control circuit. The ISL6251 charge control chip is a highly integrated battery charge controller that not only controls the battery charging process of the laptop, but also controls the power supply between the power adapter and the rechargeable battery by controlling the externally connected FET. The ISL6251 charge control chip has accurate charging current limiting function, and its charging voltage accuracy can reach ±0.5% (-10°C～100°C), thus ensuring the safety of the battery charging process and prolonging the service life of the rechargeable battery, as shown in Figure 1. The pin diagram and internal functional block diagram of the ISL6251 charge control chip are shown.

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Figure 1 diagram of the chip for ISL6251

Figure 1a Functional block diagram

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Before starting to study I advise you to download schematic Compal LA-7321P, so you can follow and understand the voltages.

Figure 2 ISL6251 charge control chip Functional block diagram As shown in Figure. 2, the FET PQ102 and the FET PQ103 in the circuit mainly function as a power supply switching function in the circuit. When the power adapter is plugged in and normal, the FET PQ102 is turned on, and the motherboard of the laptop is powered by the power adapter. When no power adapter is supplied or the power adapter is not powered properly, the FET PQ103 is turned on and the laptop's motherboard is powered by a rechargeable battery. The resistor PR101 in the 19th pin and the 20th pin connection circuit of the ISL6251 charge control chip is used to detect whether the input current of the power adapter is normal. The FET PQ110 and the FET PQ108 in the 14th and 17th pin connection circuits of the ISL6251 charge control chip control the on and off of the two FETs by the output drive control signal. The power supply of the FET PQ108 comes from the input power of the power adapter. The inductor PL101 mainly functions as an energy storage device in the circuit. The capacitor PC101, the PC102 mainly function as a filter in the circuit. The 21st pin and the 22nd pin of the ISL6251 charge control chip are connected to the resistor PR102, which is mainly used to detect whether the charging current of the battery is abnormal.

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The input power of the power adapter is charged by the FET, inductor and capacitor in the charging control circuit, and the rechargeable battery is charged. The whole process is controlled by the charging control chip. 1.3 standby circuit and system power supply circuit 1. Standby circuit The standby circuit of the laptop computer is a laptop power supply circuit capable of providing 3.3V and 5V power supply in standby mode. When the laptop's motherboard has a power adapter or a rechargeable battery, the standby circuit is already working. The standby circuit converts the power supply of the protection circuit output to more than ten volts to 3.3V and 5V standby power, and supplies the chip, circuit and related equipment that need standby voltage, such as the chipset, EC chip, and host power supply key on the motherboard, prepare for the boot of the laptop. In the design of the standby circuit, there are certain differences between different manufacturers and models of laptop. In the specific laptop maintenance process, the composition of the standby circuit and its output can be judged and analyzed according to the power-on sequence of the faulty laptop. Powered by. The standby circuit of the laptop is the basis for the normal startup of the laptop. In the maintenance process of many laptops, the standby circuit needs to be first tested to determine the scope of the fault. Therefore, it is very important to master the working principle of the standby circuit. 2. System power supply circuit The system power supply circuit of the laptop is also a very important power conversion circuit on the laptop motherboard. Unlike the standby circuit, the system power supply circuit is in the laptop boot process and during the running process, for each laptop. Chips, circuits, and related hardware devices provide 3.3V and 5V power. After the system power supply circuit of the laptop starts to work normally, the power supply of the ten volts supplied by the protection isolation circuit is converted into a system power of 3.3V and 5V. Many of the chips, circuits, and related devices on the laptop's motherboard require both power supplies to function properly. The relationship between the standby circuit of a laptop and the system power supply circuit is very close. In many cases, it is necessary to first recognize the structure and principle of the standby circuit, in order to further analyze the system power supply circuit of the laptop.

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The standby circuit and system power supply circuit of the laptop are the basis of the booting process and normal operation of the laptop. When the electronic components in the two circuits are damaged or have problems such as soldering and desoldering, the laptop usually fails to boot normally. Startup and automatic restart and other failures. 3. Analysis Linear Regulated Power Supply Type Standby Circuit Figure 3 shows the laptop standby circuit diagram consisting of two linear regulators, LP2951 and G913CF. The power supply DCBATOUT output from the protection isolation circuit is input from the 8th pin of the linear regulator LP2951. After the conversion of the internal circuit of the chip, a 5V standby power supply named 5V AUX S5 is output from the first pin. A chip, circuit, and related device that requires a 5V standby voltage for the laptop in standby mode.

Figure 3 standby circuit diagram After 5V_AUX_S5's 5V standby power supply output, it will enter the chip through the 3rd pin of the linear regulator G913CF. After the internal circuit of the linear regulator G913CF is converted, it will output a 3.3V called 3D3V_AUX_S5. Standby power supply, providing chips, circuits and related equipment that require 3.3V standby voltage in standby mode.

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As can be seen from the circuit diagram, the standby circuit converts the power supply provided by the isolation circuit into a standby power supply of 5V and 3.3V. The core of the whole conversion process is the linear regulator in the circuit. It can also be seen that the standby circuit of the linear regulated power supply type has a simple structure and requires a very small number of electronic components. 4. Switching power supply type standby circuit The ISL6237 power control chip is a versatile, highly integrated and efficient power control chip that is widely used in the power supply circuit of laptop motherboards. ISL6237 power control chip has wide input voltage range (5.5~25V), soft start and soft stop, thermal shutdown, dual fixed 1.05V/3.3V and 1.5V/5.0V output or adjustable 0.7~5.5V and 0.5~2.5 V output and other features, as shown in Figure 4 is the ISL6237 power control chip pin diagram and internal functional block diagram.

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Figure 4 detail Functional diagram ISL6237 The ISL6237 power control chip integrates a pulse width modulation (PWM) controller and a linear regulator, which can be used to drive the 3.3V and 5V power supply of the rear stage circuit. Figure 5 shows the application circuit diagram of the ISL6237 power control chip.

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Figure 5 diagram of the ISL6237 power control chip The fourth pin of the ISL6237 power control chip is the on chip linear regulator signal open end. When the 4th pin gets a high-level turn-on signal, the linear regulator function module inside the ISL6237 power control chip starts to work. After that, the 7th pin of the ISL6237 power control chip outputs the power supply named VL. Power is supplied to the relevant pins of the ISL6237 power control chip and related circuits. The 14th pin of the ISL6237 power control chip and the EN1 and EN2 terminals of the 27th pin are the signal enable terminals of the internal circuit of the ISL6237 power control chip. When these two pins get a high-level start signal, the ISL6237 power control the internal circuit of the chip starts to work, and outputs relevant control signals to drive the relevant electronic components of the subsequent stage circuit to enter the working state. The control signals output on the 15th and 18th pins of the ISL6237 power control chip are mainly used for the FET PQ43 and the FET PQ40 in the driver circuit, and then pass through the storage inductor PL10 and the filter capacitor in the subsequent stage circuit. Finally, the power provided by the protection isolation circuit is converted into a 5V standby power supply to the chip, equipment and related circuits that require a 5V standby voltage.

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The control signals of the 26th and 23rd pins of the ISL6237 power control chip are used to drive the FET PQ42 and the FET PQ41, and then pass through the energy storage inductor PL11 and the filter capacitor in the subsequent stage circuit, which will eventually protect. The power supply provided by the isolation circuit is converted to a 3.3V standby power supply to a chip, device, and related circuits that require a 3.3V standby voltage, such as a host power supply key, an EC chip, and an RTC circuit. During the startup and operation of the laptop, the ISL6237 power control chip and its related circuit output 3.3V and 5V power supply, under the control of the relevant signals, the relevant circuit is converted to 3.3V and 5V system power supply, providing 3.3V And 5V power supply chip, equipment and related circuits, such as chipset, etc., as shown in Figure 6, is the circuit diagram of standby power supply converted to system power supply after power on.

Figure 6 diagram of standby

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1.4 CPU circuit The CPU is the core of the laptop motherboard, and the importance of the power supply circuit that guarantees its normal operation is self-evident. Because the CPU is very integrated and complex hardware and the working conditions are more demanding. Therefore, the CPU power supply circuit is also the power supply circuit with the highest design requirements in the power supply circuit of the motherboard, and is also one of the circuits with high failure rate. The CPU power supply of the laptop motherboard can be divided into core power supply and auxiliary power supply. The CPU core power supply circuit is usually located near the CPU socket of the motherboard. The CPU is one of the most power-consuming chips in a laptop motherboard, especially its core power supply has a relatively low supply voltage but relatively large supply current. Early CPU power supply usually used single-phase power supply circuit, but with the improvement of CPU performance and working conditions, the current CPU power supply circuit is a multi-phase power supply circuit. In a multiphase power supply circuit, each phase is relatively independent but symmetrical, and the current generated by each single phase eventually converges to provide a low voltage, high current supply to the CPU core. Some CPU power supply circuits are also designed with FET drivers for better drive circuit operation. The FET driver, also known as the power control chip or driver IC, has the characteristics of signal amplification and high voltage resistance, and is mainly used to better drive the FET in the circuit. At present, the power supply of the laptop CPU can be divided into three parts: The CPU core power supply, the display core power supply and the auxiliary power supply integrated in the CPU. As shown in Fig. 7, the CPU power supply connection circuit diagram of the Intel laptop motherboard is shown.

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Figure 7 CPU circuit diagram

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Figure 7a +CPU CORE

Figure 7b+ GFX CORE power supply

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As shown in Figure 7a, the +CPU CORE supply powers the core of the CPU, which is typically provided by a CPU power supply circuit located near the CPU socket of the motherboard. As shown in Figure 7b, the +GFX CORE power supply is the power supply for the integrated display core in the CPU. This power supply is also typically provided by an independent switching regulator power supply circuit. As shown in Figure 7. The CPU is connected to the ground circuit. For a CPU with high power consumption, a large number of grounding wires can effectively ensure the safety and stability of the CPU. As can be seen from Figure 7, the CPU needs voltage when it works normally. A variety of power supplies with different currents can ensure that the functional modules integrated in the CPU work stably. The various power supplies required by the CPU are provided by a dedicated switching regulator power supply circuit, and some are converted by other power supply circuits. Several important CPU power supply circuits are specifically described below. 1.5 CPU core power supply circuit The CPU core power supply circuit provides a core power supply circuit for the CPU of the laptop motherboard, and is a switching power supply circuit, which is usually composed of a power control chip, a field effect transistor, an inductor, a capacitor, and a resistor, and the like, wherein the power control chip It is the core of the circuit, not only has the function of driving and controlling the circuit, but also the functions of detection, monitoring and protection. The power control chip can monitor the voltage and current changes of the output of the power supply circuit through the circuit connection of the relevant pins, thereby ensuring the stability of the current and voltage supplied to the CPU. When the power supply circuit is abnormal, the power control chip can turn off the circuit output, thereby protecting the entire circuit and the CPU. The power control chip outputs a control signal through the relevant pin to control the on and off of the FET in the circuit, thereby converting the power provided by the upper power supply circuit into the core power supply of the CPU. The difference from the fixed voltage output power supply circuit is that the voltage value of the CPU core power supply is dynamically changed. This requires that the power supply control chip in the CPU core power supply circuit should first understand the power supply voltage required by the CPU, and then drive the power supply.

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The circuit produces the power required by the CPU. The power supply information is transmitted between the CPU and the power control chip through the VID technology. VID technology is a voltage identification technology. The VID pin on the CPU outputs a coded signal to the power control chip in the CPU power supply circuit. The relevant function module inside the power control chip decodes the encoded signal transmitted by the CPU, thereby obtaining the power supply information required by the CPU. According to the power supply information transmitted by the CPU, the power control chip drives the latter circuit to output the power required by the CPU. The TPS51621 power control chip is a buck controller for CPU and GPU core power supply circuits. It features a simple external connection and a wide input voltage range. Its internal integrated MOSFET driver can effectively drive the FET in the circuit. The TPS51621 power control chip also has current limit and voltage protection functions. Figure 8 shows the application circuit diagram of the TPS51621 power control chip. As shown in Figure 8, the TPS51621 power control chip's 14th pin, 15th pin, 16th pin, 17th pin, 18th pin, 19th pin, and 20th pin are TPS51621 power supplies. The VID signal connection terminal of the control chip is directly connected to the VID signal pin of the CPU for transmitting the VID signal.

Figure 8 TPS51621 power control chip

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The 21st, 24th, 27th, and 30th pins of the TPS51621 power control chip are used to output the drive signal, control the FET PQ 15, FET PQ16, FET PQ 17, field effect The PQ 18, the FET PQ42, the FET PQ43, the FET PQ44, and the FET PQ45 are turned on and off, thereby converting the power supply provided by the protection isolation circuit into the power supply required for the normal operation of the CPU. The inductor PL10 and the inductor PL11 in the circuit function as energy storage. The +CPU CORE power supply of the final circuit output will be directly sent to the CPU core to ensure the normal operation of the CPU. 1.6 Memory circuit 1. Basics The memory used by laptops is typically a separate PCB board that communicates with the laptop motherboard through SO-DIMM slots and is powered. The memory module mainly includes memory chips, SPD chips, and electronic components such as capacitors and resistors. The memory supply circuit on the laptop motherboard needs to supply the voltage and current required for normal operation of the memory chip and the SPD chip, and also to supply power for communication between the memory and the CPU or the north bridge chip. 2. Circuit analysis is shown in Figure 9 for the laptop power supply connection circuit diagram. It can be seen from the figure that the current DDR3 type memory commonly used in laptop motherboard mainly needs +1.5V, +0.75VS and +3VS power supply. The +1.5V power supply is the main power supply for the memory, the +0.75VS power supply provides the reference operating voltage for the memory, and the +3VS power supply is mainly used for the SPD chip of the memory.

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Figure 9 DDR3 circuit diagram As shown in Figure 10, the +1.5V main power generation circuit of the memory is a switching regulator power supply circuit. The FET control circuit turns on and off the FET, and through the inductor energy storage and capacitor filtering in the circuit, converts the power provided by the protection isolation circuit into the 1.5V main power supply required for DDR3 memory.

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Figure 10 +1.5V main power The 0.75V reference operating voltage required for DDR3 memory is typically provided by a linear regulated power supply circuit next to the memory slot. The power required by the SPD chip of the memory can be supplied by the output power of the system power supply circuit through the conversion of the relevant electronic components.

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B+ Supply with Hp Adaptor Cq40 is commonly using and very often find a laptop and its circuit is very basic similarities with other hp models. So I explained its main power source B+ Supply section First. It is operate with hp’s 3 pin adapter architecture. It is very often used by others companies like Dell, Lenovo etc. It protects the system with external overvoltage and surges. When there is damage to the circuit it stops output from the adaptor. ID signal is used to operate charging Enable function.

ID

GND

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There are two operations made when plugging in an adaptor: 1. Enable B+ supply through an adaptor 2. Disable supply through a battery

Enable B+ supply through adaptor So when Adaptor is plugged in voltage (dc jack pin no.1 AD pin) through PL1 signal VIN it is usually 18.5V. VIN is going through Drain to Source PQ101 to pin 2 signal before generating pin 4, Gate B+ and CHG_B+ necessary to drive down gate voltage of PQ103 for Source to drain unlock.

The gate voltage of pq103 is control by PQ109 with PACIN Signal. When PACIN signal high it drives PQ109 gate and Drain to the source of PQ109 open and drop gate voltage of PQ103 through PR109(150k) resistance. Voltage B+ generated through PQ103, this is main system Voltage which is required for high side MOSFETs of supply sections.

Disable supply through battery When Adaptor is present VIN through PR103 is present at the gate and make PQ102 gate high for reverse protection it block a high voltage of adaptor which is usually 18.5v to attack battery BATT pin of the battery connector. ACOFF# high through pd101 ACOFF# make pq102 gate high enable when the adaptor is present.

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When the adaptor is not the present ACOFF signal is come and PQ105 low ACOFF# low and battery supply enables B+ high with appropriate amp.

Under voltage and Overvoltage Detection Cq40 has an external section for under and over voltage section in latest charging ICs has inbuilt this section and operate directly by an ACDRV signal. But in CQ40 done by LM393 comparator IC. PU102 (LM393) 8th pin power pin 2 power from a source of pq102 and pq103 through pr125 (47omh). Pin no.6 has fixed voltage 1.24Vref which is maintained by PU104 IC through PR136. PIN no 5 is get voltage from voltage divider bridge made by PR126 and PR133.if pin 5 has a voltage higher than pin6 (1.24v) pu102 output to pin7 (PACIN) makes high. If a voltage is lower than pin6 (1.24v) no voltage on pin7 (PACIN). It is under voltage protection.

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When Pin5 has voltage is higher than 3.15 or zanier diode PD103 capacity PD103 short to ground to protect overvoltage.

LED indicator Enable PACIN drive also pq114 MOSFET which low gate voltage of PQ3 which open source to drain supply and led compete it circuit and begin to glow.

COMPAQ CQ40 Standby Supply Description CQ40 Standby Supply If CQ40 laptop has a good B+ main supply which necessary for the system to turn on always supplies (3VL and 5VL). Always supply is to maintain the system in a ready state before pressing the power button.TPS51125 is used in CQ40 for standby supply regulation. LDO or Standby section In Compaq CQ40 B+ (18.5v) supply apply to pin16 of tps51125 It receive power supply for IC’s LDO (3.3v and 5v)

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Standby supply section and makes EN0 pin13 high and connect to GND with 620k resistance. EN0 is the control pin of VREG5 pin17, VREG3 pin8 and VREF pin2 regulators. Bring this node down to GND disables those three regulators and minimises the shutdown supply current to 10 μA. Pulling this node up to 3.3 V or 5 V will turn the three regulators on to standby mode.

Given below table is shown the sequence:

VREF volt which is typically 2v fix voltage which is connected to TONSEL pin4 for set ch1 and ch2 frequency to 245KHz and 305KHz respectively and VREF is also connected with SKIPSEL for auto skip function. It’s also supply inner logic for VREG5 and VREG3 STANDBY SUPPLY.

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VREG5 and VREG3 STANDBY SUPPLY output respectively with 100mA load The VREG5 serves as the main power supply for the analogue circuitry of the device and provides the current for gate drivers. The VREG3 is intended mainly for auxiliary 3.3-V supply for the notebook system during standby mode. It provides supply to I/O chip, on-off logic etc. Note: in CQ40 VREG5 is +5VL and VREG3 is +3VL Turn ON switch mode power supplies (channel-1, channel-2)

When LDO section enables the two switch mode power supplies (channel-1, channel-2) become ready to enable at this standby mode. The TPS51125 has an internal, 1.6 ms, voltage servo soft start for each channel. Each Channel is enabled by ENTRIP1 pin1 and ENTRIP2 pin6 respectively. For this, there is a little logic. There are types of input to make high both ENTRIPX one is ACOFF and second is EC_ON. ACOFF is input when an adaptor is inserted in DC JACK I/O makes low ACOFF signal by NOT GATE (74lvc14 IC) logic output on the gate of pq308 and drop down Drain Voltage to GND by this Gate voltage of both pq305 and pq306 is low and high the Drain voltage which is EnTRIP1 and ENTRIP2.

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When the ENTRIPX pin becomes higher than the enable threshold voltage, which is typically 430 mV, an internal DAC begins ramping up the reference voltage to the PWM comparator and make the gate voltage high and both channels are enabled output +3VALWP and +5VALWP STANDBY SUPPLY respectively. When all output is good it releases power good signal from pin23 for EC to release RSMRST#.

Over Voltage And Under Voltage Protection TPS51125 monitors a resistor divided feedback voltage to detect over and under voltage .which is usually done by VFB1 pin2 and VFB2 pin5. When the feedback voltage becomes higher than 115% of the target voltage, the OVP comparator output goes high and the circuit latches as the top MOSFET driver OFF and the bottom MOSFET driver ON. TPS51125 monitors VO1 pin24 and VO2 pin7 voltage directly and if it becomes greater than 5.75 V the TPS51125 turns off the top MOSFET driver. When the feedback voltage becomes lower than 60% of the target voltage, the UVP comparator output goes high and an internal UVP delay counter begins counting. After 32 μs, TPS51125 latches OFF both top and bottom MOSFETs drivers and shut off both drivers of another channel. This function is enabled after 2 ms following ENTRIPX has become high.

HP CQ40 Battery Charging Discription Laptop battery is charged by an external power. Which is usually output dc voltage and provide power to system and charge battery simultaneously. When battery fully charged continue supply to the system through the adaptor and cut battery charging.Every laptop has his own type of configured battery charging circuit. The charging process is managed by multi-controllers like: • Charging ic • KBC I/O controller (for battery temperature, level, enable and adaptor detection) • Battery internal ROM chip or external ROM u28 (battery must be connected) First of all system supply B+(main supply source) is available for system startup

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ADP_ID or Adaptor Id pin Function: (fault cause: unknown adaptor or not battery charging) When adaptor is connected output trough adaptor ID pin (centre pin of adapter) output voltage about 14.V to 18V after this PR3 and PR2 voltage divider drop voltage to 3.3v and it goes to KB926 I/o controller pin no.66 in AD input section. It converts this analogue signal to digital which is necessary to identify adaptor type (60w or 90w). If ADP_ID signal is no voltage or below 2V it shows unknown adaptor type or not charging due to wrong ID detection in windows. Note: CLK for enabling charging another signal is important like BATT TEMP, BATID, BATDATA a CLK lines

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S

Battery identification and Level detection (fault cause: no battery detect) CQ40 Battery connector has 8pins: 1. Ground 2. Ground 3. Battery temperature BATT_TEMP signal (when battery is connected it is below 2.7v (BATT_TEMP) or about 1.4v.when it is 3.3v no battery is present. It goes to I/O pin no. 63 AD input section) 4. Battery ID BAT_ID signal (this signal is for battery identification to describe battery type and a number of cells used in battery .it goes to charging IC pin no.20 (cells). 5. Battery SMBus clock signal (this signal is for the clock to run data between I/O pin no 77 and battery.) 6. Battery SMBus data signal ( it transfer data between I/O pin no.78 and battery for determining how much battery is charged. It is responsible for making FSTCHG signal high to enable charging if the battery is low from it full condition. 7. Battery V+ voltage for system supply( It go through pq102 to B+ main supply source) 8. Battery V+ same as pin no 7.

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BATT_TEMP pin no.3 is for battery identification that battery is connected and in good temperature. It is below 3.3 v for detecting battery. If it is 3.3v no battery detects. For battery level EC_SMD and EC_SMC signals are responsible it should be at 3.3V always.

Adaptor detection for charging IC and Enable charging

When the adaptor is connected PU102 makes output to pin no.1 when pin no.3 is higher than 1.24 vref. when pu102 pin no.2 is high it goes to I/O chip for ac adaptor connect information To system with the requirement and on PQ112 gate pin no.2 for convert FSTCHG# to CHGEN# for enabling or disable charging. As given above 1. Adapter is connected ADP_ID is senses 2. Battery is connected BATT_TEMP lower than 3.3v 3. SMBus is connected and has 3.3v and battery is not fully charged I/O chip release FSTCHG signal to pq113 which goes to ACDET pin no5 to PU101 (charging IC).

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When ACDET is above 2.4v charging ic detect a valid adaptor for charging.PQ113 gate gets FSTCHG signal it switches down to low CHGEN# signal for enabling charging. There are other pins also which should make some requirement for proper charging • PVCC pin no.28 is higher than 5v (must be high for all bias enabling) • ACDET pin no.6 is higher than 2.4V(under voltage is enable when lower than 2.4v) and lower than 3.15(overvoltage is enabled when higher than 3.15v) • CHGEN# pin no.1 is low to 0v(0v=enable, 3.3v=disable) It makes output on VREF pin no10 (3.3v) which is connecting to cells pin no.20 for 4 cell battery Charging condition available. There is another output on region pin no 24 (6v) for boost battery charging.

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Adaptor current sensing and input For adaptor current sensing Charging IC gets input to internal comparator from pr102 at ACP pin no.3 and ACP pin no.2 which compare difference and output ADP_I pin no.15, it goes to I/O pin no.65 AD input. I/O output ACSET from pin no.72 for set adaptor current set pin no.6 of charging IC. VDAC pin no11 is connected to 3.3v always for reference input for VADJ pin no 12 by voltage divider set charge voltage. It is between 2.4 to 3.6 v IDLE. Charge current is set by SRSET pin no.16 by the external voltage from I/O IREF signal. When given condition meets battery charging process started: • CHGEN is LOW; • Adapter is detected; • Adapter is higher than PVCC-BAT threshold; • Adapter is not over-voltage; • REGN(6V) and VREF(3.3v) are valid; • Thermal Shut (TSHUT) is not valid(temperature should be under 130 degree) Charging is enabled (CHGEN# =0v) charging IC makes output on the gate of high side MOSFET PQ108 and on the gate of low side MOSFET PQ110 for charging voltage produce on pin no 25 (ph) through pl102 to the battery.

Battery Full Charge detection Voltage through pr112 to battery and charge battery, charge current and voltage difference id detects by SRP pin no.19 and SRN pin no.18 .when SRP and SRN have true(SRP>SRN) IC regulate the charge MOSFET gate. When SRP=SRN it stops output on HDRV and IDRV to stop battery charging. it is battery over-voltage condition when the battery is charged up to 104% (detect by BAT pin no.17) it stops charging , it never start again until battery falls down to 102%.

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Why need to Convert or Bypass the DIS Graphic to UMA in Laptop? Most of the old or outdated laptop, when their mainboard/motherboard DIS graphic broken, it is need to replace the DIS graphic chip. Unfortunately, the price of this chip is quite expensive. Also hard to find the good & new chip. Most of this DIS chip selling by the seller is refurbish or used from the old or junk laptop motherboard. So the purpose to use this method “Bypass DIS to UMA graphic” is: 1) Save the cost of repair laptop with lower fees. So the customer need to repair their outdated laptop. 2) Cannot find/buy the DIS graphic BGA chip. 3) Some models of laptop motherboard have DIS design problem (for example the Apple A1286, A1297, A1398, HP CQ42 & etc laptop), even replace with a new DIS graphic chip. After use several months, the same problem occurs. Especially the A1286 motherboard, most of the time is their graphic chip location PCB (inside layer) circuit line/s broken/abnormal inside. So need to use this method to save the laptop. 4) If the laptop owner is not a gamer or graphic designer, and they just want to use laptop running steady and battery can long lasting. For example, the laptop just uses in office or for business use only. When compare with DIS graphic, the UMA graphic is using more less power than the DIS graphic. So the laptop will less heat generate inside the laptop and it can long lasting to use too. Note: Some of the model laptop has built-in two types of graphic design (UMA & DIS). The method on bypass their DIS to UMA have two, one is through software and another one is through hardware. For the software method, if the laptop has built-in two types of graphic DIS & UMA, also their BIOS has function to control it, then just login into their laptop motherboard BIOS to select/choose the DIS or UMA type graphic easily without using the bypass method. Another software method is to root/programed the “special” BIOS into laptop motherboard to bypass their DISCRETE and use the UMA display. For the hardware method, usually is to remove their discrete power supply coil/s and transfer their LVDS interface resistor to the right position.

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If this method not success, go to next steps to remove or transfer some components to match the laptop mainboard to working in UMA circuit. Different design of laptop mainboard and different generation of their chipset have different modification method. Commonly method is remove their DIS BGA chip, shift or transfer some component to match the UMA circuit, shift/transfer component in LVDS interface, Bridges and so on. CAUTION: Before starting to do laptops bypass the DIS to UMA, make sure you know what you’re doing, and you have a confident knowledge in laptop motherboard-mainboard repair. For the Apple laptop, after modification and bypass their graphic from DIS to UMA, the Apple laptop CANNOT install Windows system!! Some of the technician they use a ‘not perfect’ BIOS solution or that part number motherboard is not suitable to root the BIOS. Even it is successful to root the BIOS and can use their UMA display, but some of the laptop function will miss, for example, the sleep mode after activating and when back to normal mode, their screen display is darkness or abnormal display! Some also complaint the Apple system will running slow and lack too, after bypass the DIS on motherboard. So you need to know what you’re doing first, before starting to do the modification.

The Secret Tips on How to Convert or Bypass the Laptop Motherboard Discrete to UMA Graphic Below information are the secret tips on how to bypass the motherboard Discrete graphic card to UMA integrated graphic card. Not just follow the DIS to UMA photo to do it only. But you also need to know how to do it with different Bridge architecture use the different method to do their modification.

Intel HM4X Series Dual Bridge Architecture Motherboard DIS to UMA Method (A) North Bridge has integrated graphic card (UMA) function, for example: GM45/GL40, etc, change as the following methods (Attn: Not all need to use):

1) Change LVDS jumper resistors to North Bridge. 2) Change the EDID panel BUS (READ) to North Bridge. 3) Change High-voltage control signal and Panel power supply switched on signal to North Bridge. 4) Some models of the HM4X motherboard needs to root/programmed their UMA BIOS.

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5) Check the UMA module has the power supply connect or not. If not, manually connected the UMA module power supply. 6) Check the Clock. 7) The Panel connector port until the North Bridge in between them if don’t have the jumper resistors there, this motherboard cannot bypass the DIS to UMA. 8) When change the DIS to UMA, normally just change the LVDS module and meet the North Bridge LVDS module working condition. Other module like: CRT module, HDMI module and TV module no need to change. (B) If the North Bridge don’t have the Integrated graphic (UMA), for example: PM45/965PM, etc, change as the following methods (Attn: Not all need to use):

1) Change the North Bridge with built-in integrated graphic. 2) Change the power supply for North Bridge integrated graphic module (LVDS module). 3) LVDS signals change to North Bridge output. 4) Change the Panel EDID BUS (READ). 5) Root/Programmed the integrated graphic (UMA) BIOS. 6) Change high-voltage control signal and signal. 7) Check the integrated graphic clock. 8) The Panel connector port until the North Bridge in between them if don’t have the jumper resistors there, this motherboard cannot bypass the DIS to UMA. If it has the jumper resistors there and need to change, you need to pay attention to these symbols inside the schematic diagram: IV@, EV@, UMA, DIS, & etc. 9) When change the DIS to UMA, normally just change the LVDS module and meet the North Bridge LVDS module working condition. Other module like: CRT module, HDMI module and TV module no need to change.

Intel HM6X & HM7X Series Chipset Motherboard DIS to UMA Method Change as the following methods (Attn: Not all need to use, sometimes just one of the following methods is okay): 1) If the integrated graphic UMA is blocked, cannot be changed. (Search the schematic diagram their VAXG signal is short circuit to ground (GND) or not. 2) Direct removed several coupling capacitors in PCIE BUS, let the CPU do not recognize the Discrete graphic is okay. 3) Disconnecting the Discrete graphic power supply. For example, removed their power supply coils/inductor. (included the main power supply and secondary power supply). (This method does a lot in HM6X & 7X! Because it is the easy way to do it! )

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4) Removed the Discrete graphic chip. 5) Login to the motherboard BISO to change the display setting from DIS to UMA. 6) The HM6X series chipset motherboard, after change to UMA no need to root/programmed the BIOS. 7) The Panel connector port until the North Bridge in between them if don’t have the jumper resistors there, this motherboard cannot bypass the DIS to UMA. If it has the jumper resistors there and need to change, you need to pay attention to these symbols inside the schematic diagram: IV@, EV@, UMA, DIS, & etc. 8) When change the DIS to UMA, normally just change the LVDS module and meet the North Bridge LVDS module working condition. Other module like: CRT module, HDMI module and TV module no need to change.

AMD Dual Bridge Architecture Motherboard DIS to UMA Method 1) The AMD North Bridge has built 2) Direct remove Discrete graphic chip, change LVDS jumper resistors, change highvoltage control signal & screen panel power supply switch on signal and change the panel EDID Bus (READ). 3) Connect the North Bridge integrated graphic module power supply and clock. 4) Some model of motherboard need to root/programmed their integrated graphic (UMA) BIOS. 5) The Panel connector port until have the jumper resistors there, this motherboard cannot bypass the DIS to UMA. If it has the jumper resistors there and need to change, you need to pay attention to these symbols inside the schematic diagram: EV@, UMA, DIS, & etc. 6) When change the DIS to UMA, normally just change the LVDS module and meet the North Bridge LVDS module working condition. Other module like: CRT module, HDMI module and TV module no need to change. ** The method to bypass the motherboard DIS to UMA, not all the model/motherboard can be change. Also, NOT all the motherboard can be change successfully. Especially the motherboard is using the Nvidia graphic card/chip need to pay attention to OPTIMUS mode switching card/chip need to pay attention to BACO mode switching. **

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Part 13 Laptop Motherboard Repair Flowchart

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This is an algorithm that helps to repairman to find the problem in the short period of time. It will be helpful in such laptops: Toshiba, Dell, HP, IBM Acer, and Sony... The troubleshooting algorithm will show Basic solution way!

Power off Problem Laptop can't power on while press Power button Switch and 0.00 to 0.02 amp display on DC power supply then follow This flow chart Power Off

No Voltage on power jack

19v on power jack

Check voltage on volt in section

Problem in adapter or power jack

No voltage in P-Channel mosfet

Check volt in mosfet

Found bad mosfet or Diode, replace it, problem solve

Volt in mosfet, diode ok then replace battery charging IC, SIO

Power On

19v present in volt in section fuse

Follow task step by step 1. Dry solders motherboard 2. Replace 32khz crystal 3. Re-programme Bios 4. Check or replace power cable or switch 5. Replace charging IC, Voltage regulator IC 6. Replace SIO 7. Reflow, Reball, Replace ICH or PCH 8. Remove Ian ic and sound IC

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Dead Laptop Dead

Check 19 Volt at current sensing resister

Check VIN section Mosfet or VIN chip Check 3volt at EC BIOS pin no 8

Check step down 1 section always voltage

Check power button in 3v to 0v variation

Power button bad

Check RSMRST 3v and PM power button

PCH bad

Check SLP_S3 (SUSB) SLP_4 (SUSC)

Check pulses at EC BIOS pin no 1 while pressing power button

SIO bad Check suspend section

Power On

Bios bad

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Power on but no display Power on but no display

DC power supply amp rating is between the 0.01to 0.80 Amp

DC power supply amp rating is between the 0.90 to 1.70 Amp

Follow Step

Follow Step

1. Replace CPU and RAM 2. GMCH,RAM, GPU power supply 3. Re-programme BIOS 4. Replace SIO 5. GPU,PCH,GMCH,ICH, Reflow, Reball, Replace

1. Replace CPU 2. Re-programme BIOS 3. Dry solder 14.3mhz clock & clock IC 4. Replace SIO 5. GPU, PCH, GMCH, ICH, Reflow, Reball, Replace

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Display ok but backlight no work Display ok but backlight no work

LCD Display screen

LED Display screen

(Check on lcd screen back panel pin point voltage (40 pin Connector) (1) Pin no. 2,3 = 3v to 5v (vdd for lcd) (2) Pin no. 2,3 = Fuse (3) Pin no. 38,39,40= 11v to 19v (Led strip volt) (4) Pin no. 35 = Backlight power (3v to 5v) (5) Pin no. 36= Bl_enable (3v to 5v) (6) LED LVDS Cable

No volt on pin no 2, 3

Replace SIO

No volt on pin no 35, 36

Check nearby LVDS connector tiny micro IC volt

Replace SIO

No volt on pin no 28, 39, 40

Check 19v fuse near LVDS connector

1- Check CCFL Bulb + Inverter Circuit 2- Check inverter circuit Volt 19v, 5v

19v not found

Inverter ON volt not found (3v to 5v)

Replace SIO

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Battery Charging Problem Battery charging problem (Plug in not charging)

Device manager remove battery ACPI drive and install again

Change battery and adaptor

Battery and adaptor is ok then follow 12345-

Change discharge mosfet Change charging mosfet Change charging IC Change SIO For Dell , HP laptop check center pin circuit

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Lining Display Problem Vertical or Horizontal Line on Display

Line is stand in each position while changed screen contain display

LCD LED problem

Line is changing the direction while change screen menu like a CMOS setup, windows loading

1- RAM problem 2- GPU, GMCH, PCH Reflow, Reball, Replace

USB Problem USB Problem

Replace USB power IC or Replace USB port

Reflow, Reball, Replace ICH or PCH

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Sound Problem No Sound

Check speaker 2ohms to 10ohms

Speaker open or short change it

Speaker ok but no suond

Follow step 1- Check or replace audio jack 2- Replace amplifier IC 3- Replace sound IC 4- Replace SIO 5- Reflow, Reball, Replace ICH or PCH

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Part 14 Dictionary for Technicians

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For understanding laptop schematic, you must know abbreviation and short form name of the laptop motherboard components. And it is kind of dictionary for technicians, so these are necessary for better understanding electronic data.

Name Components Code table Components Name

Code

Capacitor

C

Resistor Diode Zener Diode Oscilator Fuse Transformer LED Inductor- coil

R D ZD or PD X F T LED L

Transistor Power Resistor Power Capacitor Integrated Circuit IC Crystal Power Diode

Q PR PC U X or Y PD

Power Integrared Circuits Power Inductor Power Transistor

PU PL PQ

Switch

SW

Definition of Term Technique Term

Definitions

DC AC Voltage Ampere Power/Watt Load

Direct Current Alternate Current Power Supply Current Flowing The amount of voltage required Load

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Voltage Definition

Definition

Signal

Input Output Negative Positive Ground Clock

Input Alternate Current Voltage have a value below 0

in Out + GND CLK

Reset Data

Input Confirmation Communicate

Reset PCI &etc

Term of Circuit

Definition

SYSTEM 3V/ 5V PCU DC IN & BATTERY Charger GPU CORE GPX CORE VCC CORE TERMAL PROTECTION DISCHARGED +1,8 V DDR +1,5 V & 0.9 CLOCK GENERATOR LVDS POWER BUTTON CONN RTC/CKT DIS UMA PWM COMPARATOR SPI FLASH (KBC) CRT LPC BUS DMI

Step-down circuit for lowering 19V to 3V or 5V Circuit for battery charging and power jack circuit in the initial gate power Circuit and voltage power supply for chip (ICH/GMCH) Circuit for processor power supply Circuit for processor power supply Circuit heat detector supply Circuit Suspend LDO Circuit power supply for RAM Circuit for produce clock signal Circuit for display on screen LCD Circuit switch on/off Connector Circuit CMOS & frequency generator CHIF Circuit VGA Externat Generator Circuit VGA InternalGenerator Circuit Pulse Widget Modulation controller Circuit Comparator Circuit BIOS Circuit for external monitor and projector Circuit Communication Digital Media Interference

Term of Circuit

Definition

Step Up Step Down DC Converter Rectifier Voltage Divider OP-Amp

Riser Voltage Lowering Voltage DC to DC Rectifier Circuit Voltage Divider Amplifier

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The motherboard common signal definition Term

Input/Output

Definition

CLK_CPU_BCLK [1:0] H_PWRGOOD H_CPURESET # H_VID [6:0] H_GTLREF CPU_BSEL [2:0] H_TEST [1:2] AUX_PWR_ON AUX_OFF V_RPWRGD AUX_PWRGD LID # LCDSW CHG_ON ADAP_IN LCD_SW [2:0] BATOFF_I BTL_BEEP RF_LED PWR_LED CHG_G_LED PM_THROTTING # SB_RTCRST CHG_REF FAN_CTRL0 CHG_I EC_BRGHT BAT_I BAT_V ADAPTOR_I DPRSLPVR H_STPCLK # H_SMI # H_FERR # H_20M # H_INTR H_INIT # H_IGNNE # PM_THRMTRIP H_THRM # H_PROCHOT #

I

Bus clock Power OK signal Reset signal Voltage identification signal GTL reference voltage Bus select signal CPU detection signal AUX voltage is turned AUX voltage shutdown signal CPU voltage is normal AUX voltage is normal Sleep-pin switch LCD backlight switch Charging open Adapter access LCD switch Battery Close Alarm tone control Wireless LAN indicator Power Indicator Charging instructions (Green) Over-temperature alarm RTC reset Charging reference voltage Fan Control Charging current setting Light and dark adjustment Charge / still charge Battery voltage identification Adapter current setting Deep sleep - the regulator signal Stop the clock signal A system management interrupt signal Floating-point error signal Address bit 20 mask signal Maskable interrupt Initialization To ignore numerical error signal Thermal alarm signal Thermal alarm signal CPU over temperature indication

I I O I I/O I

O I I I I I I I O I I/O

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BATT_TEMP EC_POWER_ON ROMCS # ROMRD # LRST1 # SLP_S3 (S4, S5) # PLTRST # PWROK RSMRST # PWRBTN # MIC_JD_SENSE # HP_JD_SENSE # ACZ_SDATAIN [1:0] ACZ_SDATAOUT ACZ_SYNC ACZ_RST # LDRQ # LFRAME # LAD [3:0] SMBCLK SMBDATA SMB SATALED # SATARBIAS (#) SATA0RXP (N) SATA0TXP (N) IDE_PDIORDY IDE_PDIOW # IDE_PDIOR # IDE_PDDACK # IDE_PDDREQ IDE_PDD [15:0] IDE_PDA [2:0] IDE_PDCS1 # USBP + (-) OC # EE_CS EE_DOUT EE_DIN EE_SHCLK LAN_RSTSYNC TP_TX [2:0] TP_RX [2:0] PCI_CLK_LAN

I O O I I O I O O I I I O O O I I/O I/O I/O I/O OD I I O

I O O O I I/O O O I/O I O O I O O I I I

Battery Identification Power on signal Chip select signal The data has been ready LPC reset signal Sleep control signal Total reset signal Power good signal Restore the normal reset signal Power button signal Within external micphon switching Within the external speaker switch Serial data input Serial data output Sync signal Reset signal DMA request LPC framework Composite line of the address data lock line Data lines Full System Management Bus SATA to read and write instructions he Serial ATA resistance bias Serial ATA0 accept Transmission of serial ATA0 I / O channel ready Disk I / O write Disk I / O read Device DMA confirmation Device requests Device data Device address Device chip select USB signal Over current protection Chip select signal EEPROM data output EEPROM data input EEPROM clock Lan Chip reset signal Transfer data Accept data Network clock

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PCI_LOCK # PCI_IDSEL PCI_DEVSEL # PCI_STOP # PCI_TRDY # PCI_IRDY # PCI_FRAME # PCI_RST # PCI_GNT # PCI_REQ # PCI PCI_C / BE [3:0] # PCI_PAR PCI_AD [31:0] DMA TV_DACB / DACC NB_CRT_REFSET NB_CRT_BLUE NB_CRT_GREEN NB_CRT_RED NB_CRT_VSYNC NB_CRT_HSYNC M_WE # M_CAS # M_RAS # M_BA [1:0] M_CS [3:0] # M_CK [4:0] / MA_CK # [4:0] M_CKE [3:0] M_DQS [7:0] M_DM [7:0] M_DQ [63:0] MA_A [13:0] H_DP [3:0] # H_DBSY # H_AP [1:0] # H_ADSTB [1:0] # H_ADS # H_TRDY # H_REQ [4:0] # H_D [63:0] # H_A [31:3] # H_CPUSLP # DPRSTP #

I/O I I/O I/O I/O I/O I/O O O I I/O I/O I/O O I O O O O O O O O O O O O I/O O I/O O I/O I/O I/O I/O I/O I/O I/O I/O I/O I I

Locking Initialize the device selection Device select signal Stop Signal from the device is ready Master device ready signal Cycle framework Reset signal Guarantee Request Bus - Peripheral Component Interconnect bus Instruction or byte Enable Parity signals Address data bus Direct access to memory TV signal transmission Resistance setting The Blue analog signal output The Green analog signal output The red analog signals output Vertical synchronizing signal Horizontal synchronizing signal Write enable Column address Row address Bank Select Chip select Clock output Clock allows Data strobe Data Masking Data lines Memory address Data parity Data bus is busy Address parity Address Strobe Address Strobe Target ready Command request Data bus Address bus signals CPU sleep signal Depth stop signal

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SIO pin description Signal Nam IMVP_PWRGD LID_CLOSE WiFi_ENABLE ECRST KS SIGNAL SMBUS DATA SMBUSC.K PRQHOT VFAN FANSIG MUTE TPDATA TPCLK USBPW_ON SUSC(SLP_S4) SUSB(SLP_S3) DNBSWON(PM_PWRBTN) NBSWON(KBC_PWRBTN) LAN_PWR ACIN AC_PRESENT S5_ON SUSPON

Type CORE TO SIO LID SWITCH TOSIO SIO TO WIFI KEYBOARD SM BUS DATA SM BUS CLOCK CPU TO SIO SIO TO FAN FAN TO SIO SIO TO AUDIO SIO TO TOUCH PAD SIO TO TOUCH PAD SIO TO USB PCH TO SIO PCH TO SIO SIO TO PCH PWR BTN TO SIO SIO TO LAN SECTION VIN TO SIO SIO TO PCH SIO TO ALWAYS SIO TO SUSPEND

MIAINON RUNON VR_ON SUS_PWROK HWPG ECPWROK(PM_PWROK| TEMP_BAT XCLK RSMR5T FRAME

SIO TO STEP 2 SIO TO STEP 2 SIO TO VRM PWM TO SIO PWM TO SIO SIO TO PCH BAT TO SIO CLOCK 32.7KHZ SIO TO PCH PCH TO SIO

clk33mhz

PCH TO SIO

PLTRST

PCH TO SIO

BIOS_RD BIOS_CS BIOS_CLK BIOS_WR

SIO TO BIOS SIO TO BIOS SIO TO BIOS SIO TO BIOS

Defination VRM cpu core voltage ok PG LIDSWITCH(magneting sensor) turn on wifi card reset signal to sio keyboard system management signal system management signal cpu hot signal turn on fan fan rpm input to sio mute audio touch pad touch pad turn on USB turn on power turn on power power on signal to pch power button 3volt to zero turn on network adopter present signal adopter present signal to pch always voltage turn on release always voltage to suspend turn on1.5v, 1.05v turn on1.5v, 1.05v turn on cpu core voltage suspend voltage ok power ok input ta sio without cpu All power ok battery temperature 32,7khz clock input resume and reset signa 3 volt frame signal from pch indicating data processing 33mhz clock signal INPUT clock dept ok Platform reset 3volt saying alI power ok reset generated sio read bios sio select bios dock signal write signal to bios

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Power Chips Code Number AA AP AP A0 A8 A3 A3 A5 A6 A8 AO AJ BD CK K0 DS EM FG GG FF JL CP FH H8 JL CB EF EP 31 C6 11 H6

RT8800PQV RT8800APQV RT8800A RT8209BGQW TR8209MGQW RT8209EGQW RT8209E RT8100PQV RT8209PGQW RT8209M RT8209B RT9607PQV RT9605BPQV RT8205B RT8209NGQW RT8223B RT8205L RT8208B RT8015B RT8208A RT8204AGQW RT8207GQW RT8209AGQW RT8208DGQW RT8204A RT8205DGQW RT8207LGQW RT8223LGQW RT8208FGQW RT8202P RT8223NGQW RT8204CGQW

CL DJ DT EQ D9 CZ CK CJ CZ DK EL FG FR FR EL CB CP DJ DY FR CL JX EQ FH DZ FF EN FG DH C7 J7 20

RT8205C RT8202A RT8205E RT8223M RT9716AGQW RT8561AGQW RT8205BGQW RT8205A RT8561AGQW RT8204 RT8015A RT8208 RT8204B RT8204BGQW RT8015A RT8205D RT8207 RT8205L RT8106GQW RT8204B RT8205CGQW RT8209LGQW RT8223MGQW RT8208B RT8113 RT8208AGQW RT8205MGQW RT8208BGQW RT8207L RT9293-20 RT8207MGQW RT8223PZQW

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Conclusion With the information you have acquired, you should have a basic understanding of how to test almost all of the electronic components found in laptop motherboard. I strongly suggest you get started right away with all of the tips and tricks you have learned from this Training E-book. What you need to do now is to buy few laptop motherboards from your favorite electronic stores and begin to assemble it. This is one of the practical ways to improve your soldering skill, testing electronic components, understanding components coding and part number and etc. Once you are good in testing electronic components you then can look for junk/broken laptop motherboard to repair to perfect your repair skill. I wish you all the best and look forward to hearing your success story.

To your success.

www.LaptopRepairSecrets.com

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