Macbook Repair Guide Repair Case v1 [PDF]

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Macbook Repair Guide Repair Case v1

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Macbook Repair Guide Repair Case v1

Disclaimer This eBook has been written for information purposes only. Every effort has been made to make this eBook as complete and accurate as possible. The purpose of this eBook is to educate. The author " LaptopRepairSecrets " do not warrant that the information contained in this eBook is fully complete and shall not be responsible for any errors or omissions. The author "LaptopRepairSecrets" shall have neither liability nor responsibility to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by this eBook.

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Macbook Repair Guide Repair Case v1

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Macbook Repair Guide Repair Case v1

Table of Contents Note: Some words meaning in this E-Book.............................................08 How does a MacBook Power Up?..............................................................10 MacBook Power Up Sequences & PPBUS_GH3 Voltage......................13 MacBook Logic Board PM_SLP_S4_L Signal Timing & Voltage...........16 MacBook SMC Circuit and PPBUS_G3H Voltage Adjustment.............26 MacBook Logic Board Power Rails and ALL_SYS_PWRGD...................29 MacBook Air A1466 doesn't Boot..............................................................34 MacBook Pro doesn't Boot (Abnormal PG signal).................................39 MacBook Pro Small Current doesn't Boot Problem..............................43 13-Inch MacBook Pro doesn't Boot (Unstable Voltage)......................48 MacBook Air doesn't Boot (Short-circuit)................................................52 Apple iMac A1418 doesn't Boot.................................................................57 MacBook Pro A1706 doesn't Boot (Burned Capacitor)........................62 How to Fix MacBook Air A1466 Boot Failure..........................................65 MacBook Pro won't Turn on (Damaged Resistor).................................69 MacBook Air A1466 won't Turn on...........................................................75 MacBook Pro 13 A1708 won't Turn on.....................................................80 MacBook Air A1369 won't Turn on (no power light)............................84 MacBook A1466 Green Power Light not Lit…..........................................87

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MacBook Pro A1502 won't Turn on (CPU Short-circuit)......................91 MacBook Air A1466 CPU Short-circuit......................................................96 MacBook A1466 won't Turn on after Water Damaged.....................101 MacBook Air keeps Restarting after Water Damaged……………………..105 MacBook Pro won't Turn on after Liquid Damaged...........................109 Water-damaged MacBook Pro doesn't Display after Booting.........115 Liquid-damaged MacBook Air CPU Stops Working.............................120 Water-damaged MacBook Pro A1706 13 inch…...................................124 MacBook A1502 doesn't Boot after Water Damaged........................127 MacBook Air A1370 Stuck in Restarting Loop......................................132 MacBook Pro Always Restarts Automatically.......................................137 MacBook Air A1465 Restarts Repeatedly..............................................141 MacBook Air A1466 820-3437-A Restarts Repeatedly.......................145 MacBook Pro doesn't enter the System and Auto Restarts..............149 MacBook Air A1466 820-00165-A keeps Restarting............................153 MacBook Pro A1286 Displays Blue Screen............................................157 MacBook Air Display Screen failure after Booting..............................160 MacBook Air A1466 no Backlight after Booting…................................164 MacBook Air A1466 Screen Backlight doesn't Work..........................168 Macbook Pro A1278 no Backlight………………...........................................172 MacBook Pro A1286 doesn't Display after Booting............................177

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MacBook Pro A1278 Displays Blurred Screen.......................................180 MacBook A1532 12 inch Blurry Screen Problem..................................183 MacBook Pro A1502 Screen no Display after Booting........................186 MacBook Air won't Turn on and won't Charge....................................190 How to fix MacBook Pro A1278 Battery Charge Failure?..................194 MacBook Air A1466 doesn't Charge after Water Damage................199 Liquid-damaged MacBook A1534 not Charging...................................203 MacBook Pro Battery won't Charge with PCB Repairing...................207 MacBook Pro Shuts Down when enter the System.............................212 MacBook Pro Runs Slowly when Using Battery...................................216 MacBook Pro no Sound with Motherboard Repairing.......................220 MacBook A1534 12 inch Keyboard Replacement……………….….………...223 How to Replace MacBook Pro A1398 Broken LCD Screen?...............227 MacBook Pro A1425 Keyboard Replacement.......................................230 How to Replace MacBook Pro A1706 Keyboard?................................233 MacBook Pro A1707 15 inch Display Screen Replacement……..….….235 MacBook A1534 PIN Code/Firmware Lock...........................................239 How to Unlock PIN Code/Firmware MacBook Pro A1707…………...…245

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Note: Some words meaning in this E-Book Tube = MOSFET or Transistor Partial pressure = Divider Triode= Transistor Resistance= Resistor (some time is mean the resistance, too) Motherboard = Mainboard Plate number = Model number Top tube = High-side of MOSFET Low or down tube= Low-side of MOSFET Light= Power on (some time also means screen got display) Universal meter = Multimeter

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Part-1 The Basic Knowledge

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How does a MacBook Power Up? 1. An always-on PP3V42_G3H 3.42V power rail is created directly from internal battery or a charger. This power rail powers the System Management Controller (SMC). The Mac is in “off mode" (G3) but the SMC keeps scanning the keyboard power-on button and Magsafe connector for further inputs. 2. If you connect Magsafe to the Mac, the SMC will read code from the chip on the Magsafe connector to identify the type of charger connected. The charger outputs a pre-set voltage (14.5/16.5/18.5/20) 1 second after the connection is stabilized and the charger type is identified. The green light then turns on. The charging circuit will receive power from Magsafe. A power management chip will create a PPBUS_G3H power rail, operating at 12.6V for MBP and 8.4V for MBA and Retina. The SMC reads the chip on the battery to check the battery status and therefore determine the required charging current. If the battery is empty then a high current will be applied (fast charging mode).The current will be gradually reduced when the battery is near full. The orange light turns on while battery is being charged. Once the battery is fully charged, the green light will turn on again and no current will be sent to the battery. 3. When you press the power-on button then release it, a high-low-high pulse will be sent to SMC. SMC will enable a power management chip to create a 3.3V power rail from the PPBUS_G3H rail. This rail powers up Intel’s Platform Controller Hub’s (PCH) real-time clock circuit, deep sleep power well, and suspend power well. PCH will enable the remaining power management chips to create different voltage rails (5.0V, 1.8V, 1.5V, 1.35V, 1.2V, 1.05V, 0.9V, etc. depending on hardware design) for different devices. All these power rails can be measured on the inductors (coil). Since more than 50% of faulty logic boards are related to one or more missing power rails, this information will be helpful if you decide to get it fixed by a component level repairer. 4. The memory module (RAM) will receive power first followed by the CPU, hard drive, optical drive, graphics chip, screen, sound chip, and WiFi card. DDR3 RAM will receive the 1.5V power rail (1.35V for low voltage DDR3). Mechanical hard drives and optical drives will receive the 3.3V and 5V rails. SSD drives will receive the 3.3V rail only. CPU and GPU core power rails are dynamic depending on load.

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Macbook Repair Guide Repair Case v1 5. All power rails report to the SMC by sending PG (power good) signals. If any one of these rails fail to send a PG signal within a pre-set time, the SMC would shut down all power rails except the always-on PP3V42_G3H 3.42V rail and PPBUS_G3H 12.8V/8.4V rail. Multiple voltage and current sensing circuits, in addition to other protective circuits are implemented in the MacBook logic board as safety measures. Malfunction of any one of these circuits can shut down all power rails to protect the MacBook. This is the reason why MacBooks are much harder to repair than other laptop brands. If all the power rails are fine, SMC will report to PCH and it will send a “reset” signal to the CPU. 6. Upon receiving the reset signal, the CPU will load BIOS/EFI codes (hardware specific codes stored in the ROM chip) to the memory module and execute POST (Power-OnSelf-Test). After POST, all devices including the hard drive, optical drive, USB, sound card, WiFi and GPU will be initialized and ready to go. 7. The GPU will read the code chip on the LVDS (Low Voltage Differential Signalling) or eDP (Embedded Display Port) screen circuits for resolution setting and switches on the screen image processing logic circuit and back-light circuit. The Mac will chime at the same time as screen back-light turns on. If you hear a chime but no image on the screen, shine a touch from the back of the screen through the Apple logo and if you can see the image, then the Mac has back-light problem. You may have a faulty screen (LED light or cable fault) or faulty back-light circuit on the logic board. Apple puts the back-light circuit on the logic board instead of on the screen as other brand names do. This is the major reason why other screen brands cannot be used on MacBook. This design also makes MacBook particularly vulnerable to water damage. Water can kill the 28V-50V back-light circuit instantly. 8. The CPU starts and executes BIOS/EFI’s PnP (Plug and Play) codes to allocate resources such as DMA channels, I/O port address and IRQs. 9. The CPU then executes BIOS/EFI’s input/output codes to access bootable devices such as hard drives, optical drives or USB drives, searching for an operating system loader. If no bootable drive is found or the bootable drive does not have a loader, a question mark will be displayed. If a loader is found, the Apple logo will be displayed.

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Macbook Repair Guide Repair Case v1 The CPU then executes the loader and loads the rest of Apple’s macOS software into your Mac. You will see a loading progress bar while macOS loads (older macOS uses a rotating gear image). 10. The loader loads the core macOS first followed by application and hardware drivers. MacBooks with graphics issues usually start going wrong at 2/3rds of the loading progress bar, corresponding to the moment the graphics driver is being loaded and executed. 11. Upon finishing loading, control is passed to macOS.

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MacBook Power Up Sequences & PPBUS_GH3 Voltage We will discuss the early stage of MacBook power-up sequences here. It covers the creation of PP3V42_G3H and PPBUS_G3H power rails and their normal voltages. At this level, in order to discuss in greater detail, we need to make use of Apple schematic diagrams here we will be taking the 820-3437 MacBook Air 2013 A1466 Intel Haswell CPU logic board as an example., 1. PP3V42_G3H power rail creation. The always-on 3.42V power rail PP3V42_G3H can be created directly from an internal battery or Magsafe charger shown as below:

Battery power goes through R7006, D7005 to U7090 the power management chip. Charger power also can go through R7005, D7005 to U7090. D7005 is used to prevent the 14.5V charger voltage to be delivered directly to the battery. U7090 is a low power 300mA buck converter chip. It converts 8.4V from the battery or 14.5V from the charger to 3.42V PP3V42_G3H power rail. This power rail powers the System Management Controller (SMC). The Mac is in off mode (G3) but the SMC keeps scanning the keyboard power-on button and MagSafe connector for actions. Checkpoint 1: PP3V42_G3H power rail can be measured at L7095 inductor (coil). PP3V42_G3H voltage is 3.42V.

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Macbook Repair Guide Repair Case v1 If you have a PP3V42_G3H low voltage or PP3V42_G3H shorted to ground, you need to make sure the short is not from the load side first and isolate the problem. Then check these components: U7090, R7006, R7005, C7094, R7095 and R7096. 2. PPBUB_G3H power rail creation. When we connect Magsafe2 to the MacBook, the Magsafe2 will output 3V with a limited current to test the load and detect shorted circuit. If the load is 170K then 14.5V will be output to Magsafe connector. The power management chip U7000 is responsible for creating the 8.45V power rail PPBUS_G3H shown below:

U7000 receives power from pin 2 CHGR_DCIN 14.5V then outputs 5.1V VDD on pin 19. VDD goes through R7101 and comes back as VDDP to power the PWM module of U7000. Charger 14.5V is divided by R7110 and R7111 as 3.81V feeding to pin 3 ACIN for voltage detection. 3.81V is above ACIN threshold 3.2V and SMC_BC_ACOK will be sent out from pin 14 to one-wire circuits. SMC will use the one-wire circuit to read code from the chip on the Magsafe connector to identify the type of charger. A green light indicates that the one-wire circuit and charger are both fine. Checkpoint 2: The SMC_BC_ACOK is a control signal, the voltage is 3.3V.

When the pin 2 DCIN voltage is higher than pin 17 CSON battery voltage, pin 1 output AGATE 0V and R7186 is effectively shorted to ground. PPDCIN_G3H is the MagSafe charger output, the voltage is 14.5V. This 14.5V will be divided by R7185 and R7186 and 6V will be applied to the gate of Q7180 P-channel dual MOSFET pin 3. Q7180 pin 1 and 2 source voltage is 14.5V and the gate pin 3 is 6V so the MOSFET on the left will be open. 14.5V power will go through the left MOSFET and then the internal diode of the right MOSFET to reach pin 4 and 5. 0.4V drops on the internal diode and the 14.1V power will go through R7120 for current sensing.

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Macbook Repair Guide Repair Case v1 When the current reaches to 0.4A, the 8mV voltage drop on R7120 will be sent to U7000 pin 28 CSIP and pin 27 CSIN charger current sensing circuit. U7000 will output 0V CHGR_SGATE and R7181 is effectively shorted to ground. 14.1V will be divided by R7180 and R7181 and 5.4V will be applied to Q7180 gate pin 6. The MOSFET on the right will be fully open to provide high current for more circuit power-up. And the 0.4V voltage drop will disappear. If over-current is detected, U7000 will pull up AGATE and SGATE to close Q7180, cutting off power from the charger. The PWM module of U7000 then starts to work. Pin 23 PHASE will check the PPBUS_G3H to make sure no short on this power rail and pin 24/21 output UGATE and LGATE to control Q7130 and create the PPBUS_G3H power rail. Pin 6 CELL is used to set the PPBUS_G3H “base” voltage. When CELL pulls up to 3.42V, the PPBUS_G3H “base” voltage is 12.22V (equal to 3-cell battery voltage). When CELL pulls down to 0V, the PPBUS_G3H “base” voltage is 8.1V (equals to 2-cell battery voltage). When CELL opens to float, the PPBUS_G3H “base” voltage is 4.05V (equals to 1-cell battery voltage). PPBUS_G3H “base” voltage is 8.1V for this logic board. SMC will use SMBus to communicate with U7100 to adjust the PPBUS_G3H power rail from base voltage 8.1V to the standard voltage 8.45V. You can measure PPBUS_G3H on coil L7130. Checkpoint 3: The standard PPBUS_G3H voltage is 8.45V after SMC adjustment.

If you have a PPUBUS_G3H low issue, check the SMC first. If you have a very low PPBUS_G3H voltage or PPBUS_G3H missing issue, make sure the load side is not shorted to ground then check these components: U 7100, D7105, Q7180, Q7130.

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MacBook Logic Board PM_SLP_S4_L Signal Timing and Voltage We will discuss one of the important MacBook control signal PM_SLP_S4_L and PM_SLP_S4_L voltage here. The PM_SLP_S4_L signal will transform a MacBook from the S5 state to the S3 state. We will use the MacBook Air 13” 2015-2017 logic board schematics 820-00165 as references. When will the CPU or PCH shoot out the PM_SLP_S4_L signal?

This lession discusses the prerequisites that must be met before the Intel CPU/PCH outputs PM_SLP_S4_L. In order to understand the PM_SLP_S4_L signal, we need to know the Intel CPU/PCH all in one design. Once you understand the PM_SLP_S4_L timing, a logic board with missing PM_SLP_S4_L signal issue is not hard to deal with. There are two sets of PM_SLP_S4_L prerequisites. Intel 1st to 5th generation CPUs use the same set of prerequisites called 11+1 conditions. Intel 6th generation onward CPUs use a different set of prerequisites called 13+1 conditions (discuss in a separate article). Intel and Apple use a different naming system. We use the Apple naming system by default. Since Apple uses different names referring to the same Intel CPU/PCH signal in different models, we use MacBook Air 2015 A1466 Haswell-ULT CPU 820-00165 schematics here as an example. Intel 1st to 5th generation CPUs 11+1 prerequisites for PM_SLP_S4_L: Apple Name Notation PPVRTC_G3H RTC_RESET_L PCH_SRTCRST_L PCH_INTVRMEN_L PCH_DSWVRMEN_L SYSCLK_CLK32K_RTCX1 PP3V3_S5 PM_DSW_PWRGD PP3V3_SUS PM_BATLOW_L PM_RSMRST_L PM_PWRBTN_L

Intel Name Notation (VCCRTC) (RTCRST#) (SRTCRST#) (INTVRMEN) (DSWVRMEN) (RTCX1) (VCCDSW3-3) (DPWROK) (VCCSUS3) (BATLOW#) (RSMRST#) (PWRBTN#)

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Macbook Repair Guide Repair Case v1 If PM_SLP_S4_L missing, we need to check these before replacing the CPU/PCH.

1. PPVRTC_G3H (VCCRTC) – real-time clock circuit power supply. PPVRTC_G3H voltage is 3.3V. 2. RTC_RESET_L (RTCRST#) – real-time clock circuit reset signal. RTC_RESET_L voltage is 3.3V. 3. PCH_SRTCRST_L (SRTCRST#) secondary real-time clock circuit reset signal. PCH_SRTCRST_L voltage is 3.3V. 4. PCH_INTVRMEN_L (INTVRMEN) – Intel CPU/PCH internal voltage regulators 1.05V and 1.5V enable signal. PCH_INTVRMEN_L voltage is 3.3V. 5. PCH_DSWVRMEN_L (DSWVRMEN) – Intel CPU/PCH deep sleep well (power) voltage regulator enable signal. PCH_DSWVRMEN_L voltage is 3.3V. 6. SYSCLK_CLK32K_RTCX1 (RTCX1) – clock signal for RTC circuit. It can be measured by an oscilloscope. The SYSCLK_CLK32K_RTCX1 clock frequency is 32KHz. 7. PP3V3_S5 (VCCDSW3-3) – deep sleep mode power rail. PP3V3_S5 voltage is 3.3V. 8. PM_DSW_PWRGD (DPWROK) – deep sleep mode power good signal. PM_DSW_PWRGD voltage is 3.3V. 9. PP3V3_SUS (VCCSUS3) suspended mode (shallow sleep mode) power rail. PP3V3_SUS voltage is 3.3V. 10. PM_BATLOW_L (BATLOW#) – SMC monitors the status of the battery. If the battery voltage is low, SMC will prevent the MacBook from power-up. PM_BATLOW_L voltage is 3.3V. 11. PM_RSMRST_L (RSMRST#) – It stands for “resume reset”. It means the system is ready for resuming from suspended mode (sleep mode) to power on mode. PM_RSMRST_L voltage is 3.3V. 12. PM_PWRBTN_L (PWRBTN#) – power button on/off control signal. It is a high-lowhigh pulse signal. PM_PWRBTN_L voltage is 3.3V. If the logic board is connected to the battery only, you need to press the power button on the keyboard to send the pulse signal to the CPU/PCH (via SMC). If you connect the logic board to the charger without connecting the battery, once SMC receives the SMC_BC_ACOK from charging

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Macbook Repair Guide Repair Case v1 circuit power management IC u7100, SMC will output SMC_ADAPTER_EN (ACPRESENT). In this case, the signal SMC_ADAPTER_EN will act as the same as PM_PWRBTN_L. In other words, the PM_PWRBTN_L is not always a “must" in some situation. It is why we call it “+1" condition. When the 11 prerequisites are met, once you press the power button (PM_PWRBTN_L) or connect a charger to the logic board (SMC_ADAPTER_EN), CPU/PCH will shoot out PM_SLP_S5_L, PM_SLP_S4_L and PM_SLP_S3_L to enable S4, S3 and S0 state power rails. In most models, Apple does not utilise PM_SLP_S5_L, just feedback this signal to SMC and that is all. PM_SLP_S4_L will enable the S3 state power rails including the memory module power rail. PM_SLP_S3_L will enable the rest S0 state power rails. PM_SLP_S4_L voltage

PM_SLP_S4_L is not a power rail, it is a control signal output by the PCH or CPU. The PM_SLP_S4_L signal voltage is 3.3V. PM_SLP_S5_L and PM_SLP_S3_L signal voltages are all 3.3V as well. PM_SLP_S4_L plays a very important role in MacBook power-up process. It is a power management control signal being used to transit the Macbook from standby state (S5) to power-on state (S0). A lot of MacBook power issues are related to this PM_SLP_S4_L signal missing. Lists of other important power rails and control signals and their voltage

PP5V_S3 power rail voltage is 5V PP3V3_S3 power rail voltage is 3.3V PP1V8_S3 power rail voltage is 1.8V PP1V2_S3 power rail voltage is 1.2V VBUS power rail voltage is 5V PP1V05_S0 power rail voltage is 1.05V PP1V5_S0 power rail voltage is 1.5V

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Macbook Repair Guide Repair Case v1 PM_SLP_S3_BUF_L control signal voltage is 3.3V ALL_SYS_PWRGD control signal voltage is 3.3V SMC_DELAYED_PWRGD control signal voltage is 3.3V PM_PCH_PWROK control signal voltage is 3.3V PCH_PWROK control signal voltage is 3.3V CPU_VCCST_PWRGD control signal voltage is 1.05V PM_PCH_SYS_PWROK control signal voltage is 3.3V PLT_RESET_L control signal voltage is 1.05V In the following case studies of Mac logic board repair, we will apply this PM_SLP_S#_L timing knowledge in each case to quickly identify the problems. Say goodbye to the old trial-and-error problem-solving approach, adop this advanced “measure, think, pinpoint and replace" approach. You will not only increase the success rates but also build up solid knowledge on logic board repair. This knowledge, in turn, will increase productively. Case Study 1 MacBook Model: A1278 2011 820-2936 Fault Description: water damaged, no power, PP3V3_S5 present, PP5V_S3 missing. Diagnosis: Trace PP5V_S3 enable signal P5VS3_EN_L = 3.3V, not ok. It should be low (EN_L means low-enable). Trace P5VS3_EN_L to Q7911 and find out the PM_SLP_S4_L voltage is 0V

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. Analysis: The 11+1prerequisites must be met before the Intel CPU/PCH outputs PM_SLP_S4_L. If all the prerequisites are ok, then we will consider replacing the PCH u1800. The further measurement indicates PPVRTC_G3H is 1.5V, not ok. It should be 3.3V. The suspect chips are: 1. The clock chip u2800 output low 2. The u1800 PCH pulls down the voltage (needs PCH replacement, expensive repair) 3. Resistors on the PPVRTC_G3H line R1800, R1801, R1802 R1803…. pull down the voltage.

Macbook Repair Guide Repair Case v1

Micro Soldering: We spot watermarks (very little mark, the board must have been ultrasonically cleaned by someone) on the clock chip u2800, so we replace it first. After that, the board is fully functional. In a situation like this, we always replace the easy one first. If replacing the clock chip u2800 did not solve the problem, we will remove the resistors on the PPVRTC_G3H power line before replacing the PCH. Replacing the PCH needs a BGA rework station and related BGA rework skills and the cost the repair will be much higher. Learn By Example: If we did not perform the measurement before replacing the suspected u2800, we will get this statement: “The faulty clock chip u2800 caused PM_SLP_S4_L missing." If we did the measurement before replacing u2800, we will get a much more precise statement: “The clock chip u2800 did not output enough voltage to power up PCH RTC circuit, so the PCH will not shoot out PM_SLP_S4_L". Next time if we encounter a similar situation that the PCH or the resistors on the PPVRTC_G3H line pull down the voltage and cause PM_SLP_S4_L missing, we will handle the situation with ease. A statement like "The faulty clock chip u2800 caused PM_SLP_S4_L missing" is never enough for the advanced technicians and engineers. Five of the twelve prerequisites are related to the clock chip, PPVRTC_G3H, RTC_RESET_L, PCH_SRTCRST_L, PCH_INTVRMEN_L and SYSCLK_CLK32K_RTCX1. So the clock chip should be the first chip to check if you get a PM_SLP_S4_L missing logic board. Newer models 2016 onward use a new clock chip SLG3AP3444 and it no longer outputs power rail to RTC circuit.

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Macbook Repair Guide Repair Case v1 But no matter what chip is used, we still can trace back to it by searching the PPVRTC_G3H (VCCRTC) power rail. Understand the principle and build up a personal knowledge database gradually is a “must" for a component level repair engineer. Case Study 2 MacBook Model: A1502 2015 820-4924 Fault Description: water damaged, no power, PP3V3_S5 present, PP5V_S3 missing. Diagnosis: Trace PP5V_S3 enable signal P5VS3_EN = 0V not ok. It should be high 3.3V. Trace P5VS3_EN to R8175 and R8179 and find out the PM_SLP_S4_L is missing (0V).

Analysis: Check the 11+1 prerequisites, all are good except the PM_BATLOW_L is low 0.9V. This signal is from SMC. If SMC detects a battery is connected, it will use SMBUS_BATT_SCL/SDA to get the status of the battery. If the battery voltage is lower to a preset value, SMC will keep PM_BATLOW_L as low until the battery is charged and the voltage is above the present value. If SMC detects no battery connected, it will assume the battery is ok and output PM_BATLOW_L as high (open-drain) immediately. PM_BATLOW_L is pulled up by R1410 10K resistor and the S5 rail PP3V3_S5_PCH_GPIO.

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So the suspect chips are: 1. R1410 open line or PP3V3_S5_PCH_GPIO not present on R1410 2. Q3000 pulls down the voltage 3. SMC u5000 pulls down the voltage (open drain function failed) 4. CPU u0500 pulls down the voltage (faulty CPU, replacing CPU will be expensive) Repair: 1. Measure R1410 10K, ok. PP3V3_S5_PCH_GPIO present on R1410 pin 1, ok. 2. Remove Q3000, PM_BATLOW_L is still 0.9V. 3. Remove SMC u5000, connect a 3.3V external power to pin 1 of R1410, PM_BATLOW_L is 3.3V and ok now. This result means the SMC pulls down the voltage and the CPU is OK. We need a 3.3V external power for measurement as once we remove the SMC, we will not get the S5 rail PP3V3_S5 (PP3V3_S5 is controlled by SMC_PM_G2_EN output from SMC). 4. Put back Q3000, get an SMC from a donor board, re-ball and solder back to the board. After that, the board is fully functional.

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Macbook Repair Guide Repair Case v1 Case Study 3 MacBook Model: A1466 2015 820-000165 Fault Description: No power, clean board, PP3V3_S5 present, PP5V_S3 missing. Diagnosis: Trace PP5V_S3 enable signal P5VS4RS3_EN = 0V, not ok. It should be high 3.3V. Trace P5VS4RS3_EN to R8179 and find out the PM_SLP_S4_L is missing (0V). Analysis: Check the 11+1 prerequisites, all are good except the PP3V3_SUS is low 0.1V. This power rail is from the 3.3V SUS switch IC U8020.

Repair: Check u8020 input PP3V3_S5 is 3.3V, ok. Check U8020 enable signal P3V3SUS_EN is 3.3V, ok. So U8020 must be faulty. After replacing u8020, we have a fully functional board. Case Study 4 MacBook Model: A1466 2013 820-3437 Fault Description: no power, water damage, PP3V3_S5 present, PP5V_S3 missing. Diagnosis: All the 11+1 prerequisites are present, but the PCH/CPU does not shoot out PM_SLP_S4_L. Analysis: Time to replace the PCH/CPU? NOT YET! If we cannot measure PM_SLP_S4_L on our multimeter, it doesn’t mean it does not exist. Here is the PM_SLP_S4_L signal shown on an oscilloscope.

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PCH/CPU shoots out PM_SLP_S4_L at 800ms (timeline) after PPBUS_G3H had been created and stabilised. The PM_SLP_S4_L voltage is 3.3V, perfect. But it drops to 0V at 920ms. The PM_SLP_S4_L only exits for 120ms. This is why the multimeter did not pick it up. Repair: R6120 is corroded and the SPI_MLB_CS_L signal cannot pass through. At timeline 920ms, the PCH fails to read data from SPI IC U6100 to determine the clocks and other user-definable settings, therefore, pulls down PM_SLP_S4_L. Replace the R6120 we have a fully functional board.

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MacBook SMC Circuit and PPBUS_G3H Voltage Adjustment System Management Controller (SMC) is a programmable chip containing Apple computer management codes. We will use the MacBook Air 13” 2015-2017 logic board schematics 820-00165 as references. Every Apple computer model has its own unique codes. In other words, an SMC chip from one model cannot be used in other models. The markings on the chip may be the same, but the codes in the chip matters. SMC is a very complex chip. It co-operates with Intel CPU/PCH to manage and monitor MacBook power from start to finish. We need to provide SMC power supply, SMC clock and SMC reset signals to kick-start the SMC chip shown on the below diagram:

The PP3V42_G3H power rail created by U7090 will provide main power to the SMC chip U5000 via the BGA ball called VBAT. The PP3V42_G3H also goes through L5001 to power the SMC internal logic model VDDA. The SMC will then create PP1V2_S5_SMC_VDDC for its own sensors management module to monitor system

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Macbook Repair Guide Repair Case v1 temperatures, voltages and currents. Once the SMC has received power, the SMC crystal circuit will start to output 12 MHZ square clocks for the SMC.

U5110 monitors the voltage of PP3V42_G3H. If PP3V42_G3H is stable and not less than 3.0V, U5100 will assume this power rail is safe to use and output a delayed SMC_RESERT_L signal to reset the SMC chip. The SMC_RESET_L voltage is 3.3V. The delay time is determined by the values of R5101and C5101. U5110 also outputs PP3V3_S5_AVREF_SMC references voltage for the analog-digital conversion function of SMC sensors circuits including current sensors, voltage sensors and temperature sensors. The PP3V3_S5_AVREF_SMC voltage is 3.3V.

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Macbook Repair Guide Repair Case v1 On receiving SMC_BC_ACOK signal from charging management chip U7100, SMC will communicate with the MagSafe charger via the one-wired circuit and turn on the green light on the charger. Meanwhile, SMC uses SMBus to communicate with U7100 to adjust the PPBUS_G3H power rail from base voltage 8.1V to the standard 8.45V. You can measure PPBUS_G3H on coil L7130. If the PPUBUS_G3H voltage is around 8.45V, the SMC is functioning now. At least the SMC power, clock, reset and one-wire circuits are all good. Otherwise, you have to solve the SMC issue first. SMC uses the same SMBus to read battery status to determine the battery charging current. SMS monitors system input current (AMON) and battery charging current (BMON) all the time.

When SMC receives SMC_BC_ACOK signal from the charging circuit PMIC U7100 indicating that the power charger is ready for use, SMC will send out the SMC_PM_G2_EN signal to standby circuit PMIC U7501. This signal will transform the MacBook from G2 state (Off state) to S5 state (deep sleep state). Checkpoint: SMC_PM_G2_EN is a control signal, the voltage is 3.3V. You can measure it on pin 1 of resistor R8140.

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MacBook Logic Board Power Rails and ALL_SYS_PWRGD We will discuss MacBook power sequences from CPU/PCH shoots out PM_SLP_S5_L to all system power rails (except CPU power rail) are present. We will use the MacBook Air 13” 2015-2017 logic board schematics 820-00165 as references. Apple logic board S3 power rails creation 1. The U0500 CPU/PCH outputs PM_SLP_S5_L control signal to inform the SMC (System Management Controller) that the MacBook power state transition will begin. 2. TheU0500 CPU/PCH then outputs PM_SLP_S4_L signal to U7501 PMIC to enable PP5V_S3 power rail. PP5V_S3 power rail is the first S3 state power rail and the voltage is 5V.

3. PM_SLP_S4_L signal goes pass resistor R8112, renamed as P3V3S3_EN, to enable power rail PP3V3_S3. The voltage of PP3V3_S3 power rail is 3.3V. 4. PM_SLP_S4_L signal goes pass resistor R8116, renamed as P1V8S3_EN to create power rail PP1V8_S3. The voltage of PP1V8_S3 power rail is 1.8V.

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Macbook Repair Guide Repair Case v1 5. PM_SLP_S4_L signal goes pass 20k-ohm resistor R8116, renamed as DDRREG_EN to create PP1V2_S3 power rail. PP1V2_S3 power rail is used for power the DDR3 memory chips, the voltage is 1.2V. 6. PM_SLP_S4_L signal goes pass 100-ohm resistor R8117, renamed as USB_PWR_EN to enable USB port power VBUS. The USB port power rail VBUS voltage is 5V. 7. The PM_SLP_S4_L control signal is also used to enable touchpad and Bluetooth devices. Note: These S3 power rails are not created at the same time. The RC delay circuits are used to control the delay time, therefore the timing. By changing the values of resistors and capacitors, we can get the delay time as we want. Apple logic board S0 power rails creation 1. The U0500 CPU/PCH then outputs PM_SLP_S3_L signal to transform the Mac logic board power state from S3 to S0 state (power on). 2. The PM_SLP_S3_L control signal goes pass resistor R8187, renamed as P5VS0_EN, to create PP5V_S0 power rail. The voltage of PP5V_S0 power rail is 5V. 3. The PM_SLP_S3_L control signal goes pass 20k-ohm resistor R8186, renamed as P3V3S0_EN, to create PP3V3_S0 power rail. The voltage of PP3V3_S0 power rail is 3.3V. 4. The PM_SLP_S3_L control signal goes pass resistor R8185, renamed as P1V05S0_EN, to create PP1V05_S0 power rail. The voltage of PP1V05_S0 power rail is 1.05V. This power rail is used by the Intel CPU/PCH and its system buses. 5. The PM_SLP_S3_L control signal goes pass an AND-logic gate U8180, renamed as PM_SLP_S3_BUF_L. The AND_logic gate is used to increase the strength of the PM_SLP_S3_L control signal. The voltage of PM_SLP_S3_BUF_L control signal is 3.3V.

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6. The PM_SLP_S3_BUF_L control signal goes to U7870 switch create PP1V5_S0 power rail. The voltage of PP1V5_S0 power rail is 1.5V. 7. The 3.3V PM_SLP_S3_BUF_L control signal is also used as a power rail to pull up ALL_SYS_PWRGD control signal via a 10K-ohm resistor R8167. This is why we need a powerful version of PM_SLP_S3_BUF_L instead of the weak version of PM_SLP_S3_L. Note: These S0 power rails are not created at the same time. The timing is determined by the PM_SLP_S3_L control signal and the associated RC delay circuits. The importance of ALL_SYS_PWRGD signal Apple has developed a complex validation mechanism to ensure all the power rails being created are stable and good (GD stands for good) for use. If all the power rails are good, then a valid ALL_SYS_PWRGD signal will be produced. ALL_SYS_PWRGD voltage is 3.3V. A valid ALL_SYS_PWRGD signal checks these power rails: PP1V8_S3, PP5V_S3, PP1V2_S3, PP1V05_S0, PP5V_S0, PP3V3_S0, PP1V5_S0. Any of these S3 or S0 state power rails malfunction will pull down the ALL_SYS_PWRGD signal and terminate the normal power-up process of Apple computers.

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The ALL_SYS_PWRGD signal will be reported to SMC. SMC will process this signal and prepare to create the last power rail – CPU/PCH Vcore power rail.

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Part-2 Troubleshoot MacBook doesn't Boot

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MacBook Air A1466 doesn't Boot Here is a MacBook Air doesn't boot, the problem is the capacitor on the motherboard is damaged, which causes problems with the motherboard power supply, and eventually causing the MacBook Air to fail to boot, how to troubleshoot it? The MacBook model is A1466, the motherboard model is 820-00165-A.

Firstly, we need to test the MacBook Air. Connect the MacBook Air to the power supply, the green light lights up normally. Then press the MacBook power button, the MacBook doesn't boot. Use screwdriver to remove the MacBook rear case, disconnect the MacBook battery. Connect the MacBook to the DC power supply, we can see that the current stuck at 0.037.

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Macbook Repair Guide Repair Case v1 Check MacBook Air schematic diagram and boardview. Remove the MacBook motherboard, use digital multimeter to measure the voltage for the L7130 inductor, the voltage measured is 8.5V, it's normal.

Next to find out the standby voltage 3.3V inductor, it's L7560. Use digital multimeter to measure the voltage for the inductor L7560, the voltage measured is 0.56V, which is abnormal. The standby 3.3V voltage output is abnormal, we need to check the working condition for the standby power supply chip. Check the working conditions of the U7501 chip, measuring the main power supply 23 Pin VIN voltage, the voltage measured is 0V.

Pin 23 VIN voltage

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Macbook Repair Guide Repair Case v1 According to the MacBook schematic diagram, we know that the PPBUS_S5_HS_OTHER_ISNS is connected to the PPBUS_G3H through by resistor R5430.

Find the resistor R5430 on the boardview and then use digital multimeter to measure the voltage for the resistor R5430 2 Pin PPBUS_G3H, there is no voltage, the pubic point has no voltage. The charging inductor that was initially measured has voltage, now go back to the charging inductor output side.

Pin 2 of Fuse

Measuring the voltage for the 2 Pin of the fuse F7140, the voltage measured is 0V. Disconnect the power supply, and then use digital multimeter to measure the grounding resistance of the 2 Pin, the value is 0ohm, it's short-circuited, which means the rear pole output is short-circuited.

Macbook Repair Guide Repair Case v1 Measuring the grounding resistance for the 1 Pin of the fuse F7140, the value measured is 111ohm, it's normal. Measuring the insurance, it's infinitely large, which is damaged. External connect a voltage to the 2 Pin of the fuse F7140, the external voltage can't exceed the voltage of the inductor output 8.5V.

External connect the DC power supply, and adjust the voltage to around 2V. When the current up to 3.7A, touch the motherboard with hand to check if there are chips or capacitors on the motherboard is overheat. When touch the capacitors that next to the CPU, this capacitor is overheated. Check MacBook schematic and bordview, we know this is C7324 capacitor. The C7324 capacitor is the filter capacitor on the upper tube main power supply of the CPU core power supply, the damaged capacitor caused main power supply is shorted and no output.

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Macbook Repair Guide Repair Case v1 Replace the new capacitor C7324 by hot air rework station, after replacement the grounding resistance value of the PPBUS_G3H measured is normal. Replace the fuse F7140, and then connect the MacBook to the DC power supply, the current jumps normally. Finally, assemble the MacBook Air, press the power button, now the MacBook is turned on successfully.

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MacBook Pro doesn't Boot (Abnormal PG signal) Press the MacBook Pro power button, the MacBook doesn't boot. Connect it to DC power supply to check the current, the charge current is normal, press the power button, the MacBook still won't turn on. The MacBook model is A1278, the motherboard model is 820-2936-B. We are going to fix it. First of all, we need to disassemble the MacBook Pro. Use screwdrivers to remove the screw that fix the rear case, and then open the MacBook rear case. Disconnect the MacBook battery, and then connect the MacBook with DC power supply, the current stuck at 0.45.

Disconnect the power supply, remove the MacBook motherboard to check if the motherboard has obvious water marks or traces of oxidation.

No obvious water marks or oxidation traces was found on the MacBook motherboard. Supply power to it, and then use digital multimeter to measure the voltage for each big inductor, the voltage for each inductor all are outputted

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Macbook Repair Guide Repair Case v1 normally, next we need to judge whether the MacBook logic board power supply is normal or not by measuring the SO PG signal. Check MacBook schematic diagram and boardview, find the output point of the SO PG signal.

The voltage of the U2850 4 Pin PM_S0_PGOOD measured by digital multimeter is 0V, while the normal value is 3.3V, so it's abnormal, which means the motherboard power supply output is abnormal, and it causes CPU not to work. As we know, only the 1 Pin and 2 Pin all are high level voltage, so that the 4 Pin can output high level voltage. Measure 1 Pin ALL_SYS_PWRGD, it has high level voltage 3.3V, measure the 2 Pin CPUIMVP_PGOOD, and it only has 0.11V, which is abnormal.

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Macbook Repair Guide Repair Case v1 CPUIMVP_PGOOD outputs PG by CPU core power supply IC 19 Pin.

Disconnect the power supply, switch the digital multimeter to diode mode, and then use it to measure the grounding resistance value of the CPUIMVP_PG00D.

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Macbook Repair Guide Repair Case v1 The grounding resistance of the U2805 2 Pin only has 16ohm, it's abnormal. According to the MacBook schematic diagram, we know CPUIMVP_PGOOD signal is only connect with U7400 and U2850. Use hot air rework station to remove U7400 first, and then measure it again, now the resistance value is 551ohm, it's normal.

Now we can confirm the U7400 is damaged, and it pulls down the grounding resistance value of the CPUIMVP_PGOOD signal. Directly replace it with the new U7400. After replacement, supply power to it, the current jumps properly, assemble the MacBook Pro, now it can be turned on smoothly, and all functions tested are normal, the problem has been fixed!

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MacBook Pro Small Current doesn't Boot Problem The MacBook Pro doesn't respond when press the power button, after testing, it's small current problem. The MacBook model is A1502, the motherboard model is 8204924-A, which is release in 2015. When connect the MacBook to power, the MacBook battery can be charged. Now, we need to troubleshoot the problem. Remove the rear case, disconnect the MacBook battery, connect it with the DC power supply, the current up to 0.218, and then stop.

Disconnect the power supply, remove the MacBook motherboard and measure it with the DC power supply the current stuck on 0.147. Measuring each inductor by oscilloscope, we found that the CPU power supply inductor has no voltage. Open the MacBook schematic diagram and boardview, and find the CPU power supply inductor on the boardview.

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The CPU power supply inductor are generated by ISL95826 IC, connect it to power supply to check the working condition of U7200, the voltage measured 17 Pin VIN is 12.5V, which is normal, 16 Pin VDD voltage is 5V, it's normal. Continue to measure the 1 Pin VR_0N open voltage, it's 0V, which means the CPU power supply IC didn't opened, then it causes the CPU power to not produce.

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Macbook Repair Guide Repair Case v1 CPU_VR_EN directly outputted by CPU IC, the CPU must be received CPU_VCCST_PWRGD before send out the CPU_VR_EN.

CPU_VCCST_PWRGD is outputted by U1930 4 Pin, the voltage measured for 4 Pin is 0V, and the voltage measured for 2 Pin ALL_SYS_PWRGD is 0V. Check MacBook schematic diagram to check the source of ALL_SYS_PWRGD.

The U1860 didn't install to MacBook motherboard, so we need to check which PG pulls down the voltage. First, use hot air rework station to more the inductor R8168 DDRREG_PG00D.

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After removing the inductor R8168, supply power to it, we can see that the current up to 0.5. Use Oscilloscope to measure the R8168 2 Pin ALL_SYS_PWRGD, the voltage is 3.3V, which means it's the DDRREG_PROOD pulls down the voltage of the ALL_SYS_PWRGD. Find DDRREG_PGOOD on the schematic diagram, it's outputted by IC U7400 20 Pin. Only the voltage outputted by PPDDR_S3_REG is normal, the 20 Pin can output DDRREG_PGOOD.

Measuring the waveform of the inductor L7430 front end 1 Pin with oscilloscope, the voltage outputs normally, but the waveform is abnormal, which means there is a problem with PPDDR_S3_REG output, or there is a problem with the output of the rear pole circuit.

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Macbook Repair Guide Repair Case v1 Check U7400 IC working condition. The voltages for power supply 12 pin is 5V, open signal is DDRRED_EN to 16 Pin S5, the voltage measured is 3.3V, the power supply and open signal all are normal. Now measure the VBST 15 Pin self-lifting boost Pin, the voltage is measured with an oscilloscope, and the maximum voltage can only reach 5.3V in an instant, and then it falls off quickly. The self-lifting boost Pin failure causes IC output protection.

Measuring the resistance value for the resistor R7425 with digital multimeter, the resistance value is 19.6K, the resistor is obviously damaged, replace 0 resistor, power on, use oscilloscope to measure inductor L7430 1 Pin, the waveform is stable, the output is normal. Disconnect the power, install the R8168 back the motherboard, and then supply power to it, the current jumps normally. Assemble the MacBook Pro, press the power button, now the MacBook Pro screen displays normally. After entering the system, test the WIFI, keyboard, trackpad, all are normal. The MacBook Pro has been repaired!

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13-Inch MacBook Pro doesn't Boot (Unstable Voltage) A 13-inch MacBook Pro doesn't boot after pressing MacBook Pro power button, after measurement, we found the voltage of MacBook is unstable, we suspected the unstable voltage is the main reason to cause the MacBook doesn't boot. Here is a solution to solve it, the details are as follows. First of all, we need to disassemble MacBook Pro and open the rear case of the MacBook Pro. Test the MacBook Pro again. Disconnect the MacBook battery, directly connect it to the original power supply adapter, and then press the power button on MacBook Pro, the built-in fan doesn't work, the MacBook is still not boot. Take out the MacBook motherboard to observe, there is no trace of water damage or drop damaged. Is there any problem on the circuit? We need measure the circuit on the MacBook motherboard.

Based on the MacBook Pro schematic diagram, first we need to use Oscilloscope to measure the TBA_PHASE2 of L7030. After measurement, we can see that the voltage jumps are unstable, it jumps from 0, sometimes up, sometimes down.

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From the MacBook Pro schematic diagram, we know that PM_EN_P3V3_G3H outputted by U7000 is the control signal voltage of the U6690. Now we need to test the standby voltage for PP3V3_G3H. After measurement, the output voltage of L6995 is 3.3V, which is normal.

Now we start to test L7690 by Oscilloscope. After measurement, the voltage jumps are also unstable, it jumps from 0, sometimes up, sometimes down.

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Measure the PP5V_S4 to check if the signal has been triggered. Using Oscilloscope to measure the L7670 PIN 2, the voltage also jumps are unstable. Until now, we can confirm that the MacBook Pro doesn't boot problem is caused by unstable voltage, the signal has been triggered, but the unstable voltage output causes the MacBook Power Off Protection to start automatically, so the MacBook Pro doesn't boot after pressing the power button. We need to find out the faulty part. Turn off the power supply, use multimeter to test the inductor of the each power supply, all eTest value are normal. Continue to test the voltage of the small components PP3V3_S5G, PP5V_SO, PP3V3_S4, all value tested are normal. When tested PP3V3_S0, the value is 0, it's short-circuited, the fault part is found! There are many components connected to this node, supply 3.3V to this node, after a while, the temperature of a capacitor near TYPE-C interface is higher than others, it's moldy. Check MacBook schematic diagram, we know that this PP3V3_S0_CAMERA power supply for camera. Use hot air rework station to remove the C3928, and then measure it again, now the value tested is normal. Measure the voltage of L7690 PP3V3_S5, the data is normal, and the voltage of L7420 PPVCCGT_S0G also is normal.

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Finally, assemble the MacBook Pro, press the power button, the MacBook Pro is turned on successfully!

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MacBook Air Doesn't Boot (Short-circuit) When pressed the power button on the MacBook Air, it doesn't boot and the MacBook Air screen remains black. The model for this MacBook is A1466, which is released in 2015, the motherboard model is 820-00165-A. After measuring, we found that the MacBook had a micro-current and then dropped it. It was a protective power outage, we need to fix it. Disassemble the MacBook Air, and then remove the MacBook Air motherboard. Observing the MacBook motherboard carefully, we found that the inlet sign of the MacBook screen flex cable connector had turned red, which means that there's liquid coming into the MacBook Air.

Measure it with the DC power supply, the current up to 0.3, and then drops to 0.06. Disconnect the power supply, and then supplies power to it, the situation still the same. Check MacBook schematic diagram and boardview to find the boot pin of the motherboard.

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Find the components connected to the SMC_ONOFF_L

We can boot the MacBook Air by short connecting C4834, find the C4834 on the boardview.

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Supply power to it, the current up to 0.3 and then drops to 0.06, after shortconnecting the capacitor C4834, the MacBook air still doesn't boot, which means that it was a protective power outage.

For repairing this problem, we need to use oscilloscope to measure the each power supply. Use oscilloscope to measure the each voltage, the voltage and pulse waveform measured are normal.

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Put MacBook motherboard under the microscope to observe it again, we found that there's a chip around it that's moldy. Find this chip on the boardview, it's U5110

U5110 mainly produces EC reset and EC standby 3.3V reference voltage, use oscilloscope to measure the 5 pin of U5110. Supply power to it, and disconnect the power, the 3.3V voltage always there. Next measure the 8 Pin of the U5110, there is no voltage. Disconnect the power, use digital multimeter to measure the grounding resistance, the value is 0, it's shortcircuited. Check MacBook schematic diagram, PP3V3_S5_AVREF_SMC is directly supplied to VREFA+ pin power supply of the EC, is the EC damaged? Use rework station to remove the U5110 directly, and then measure the 8 Pin again, but it's still shorted. External connect a 1.6V voltage to it, and then measure it, the current directly jumps to 3.8A, and we found the back side of the MacBook motherboard is hot.

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Macbook Repair Guide Repair Case v1 Check the back side of the motherboard, we can clearly see that there's a capacitor that's blackened.

Remove this capacitor, and then measure the 8 pin again, now the resistance value is about 700Ohm. Install the chip, and measure it again, now the value measured is 530Ohm, which is normal. Replace the new C5125, and then supply power to it, the current jumps normally. Install the MacBook air, press the power button, it boots properly, the MacBook screen displays normally.

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Apple iMac A1418 doesn't Boot After pressing the iMac power button, it doesn't respond, the iMac doesn't boot, how to fix this problem? This iMac model is A1418, the motherboard model is 820-3302-A. Remove the iMac screen, supply power to it, and the motherboard power light isn't lit. The power light isn't lit, which means the motherboard standby working condition is abnormal. Use digital multimeter to measure the voltage for the switch pin, it's 3.4V. Press the power button, it jumps from 3.4V to 0, and then jumps to 3.4V.

Check iMac schematic diagram and boardview. Measure the standby voltage PP3V42_G3H.

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Macbook Repair Guide Repair Case v1 This voltage is the first generation of the iMac motherboard.

The voltage of the inductor L7801 measured is 3.42V, which is normal. Remove the iMac motherboard.

Switch the digital multimeter to diode mode, and then use it to measure the grounding resistance value for each inductor. After measurement, we found there is a grounding resistance value of one inductor is 0ohm.

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Check iMac schematic diagram and boardview, the inductor L7610 output PP3V3_S5_REG voltage. Use tweezers to pry the inductor, the rear pole inductor 1 Pin is short-circuited, external connect one voltage to this inductor, and that voltage can't exceed 3.3V.

Touch the iMac motherboard with our hand to feel whether there are chips or capacitors are overheating, after a while, we feel the capacitor on the back side of the motherboard is overheating.

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Check schematic diagram and boardview to find this capacitor, after checking, we know it's C9680.

Directly remove the capacitor C9680 by hot air rework station, and then use digital multimeter to measure the inductor L7610, now its grounding resistance value is 113ohm, which is normal.

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Install the motherboard, supply power to it, now the power light is on. Press the power button on the iMac, the fan is running properly, and then we hear the sound of the boot, now the iMac screen should be displayed. Install the iMac screen, and turn on the iMac, the iMac boots successfully and it enters system normally.

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A1706 MacBook Pro doesn't Boot (Burned Capacitor) A MacBook Pro doesn't boot after pressing the power button, here is a solution for it. The model of MacBook Pro is A1706, which is released in 2016, the motherboard model is 820-00239-9. MacBook Pro doesn't boot is a common problem, it could be caused by many reasons, we need to measure it to find the real problem, and then we can fix it. Before we are going to fix it, we need to test it. Press the power button, the MacBook Pro has no response. Then connect the MacBook Pro to the power supply via Apple lightning cable, and then press the power button, the MacBook is still no response. First of all, power down the MacBook Pro, use screwdriver to remove the screws that fixed the rear case, and then open the rear case. Disconnect the MacBook Pro battery, connect MacBook Pro to the power supply via iPhone lightning cable, press the power button, the MacBook still doesn't response, and the fan also didn't turn.

Carefully observe the MacBook motherboard to check whether there are the obviously trace of the water or damaged. After observation, we can see that there is an obviously burned area on the MacBook Pro motherboard.

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Macbook Repair Guide Repair Case v1 Check the schematic diagram and boardview.

Find the burned components on the boardview

Search the capacitor CB703 on the schematic diagram.

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According to the MacBook Pro schematic diagram, we can know that it's the 33uF capacitor of the main power supply PPBUS_G3H. Use digital multimeter to measure the grounding resistance value for the PPBUS_G3H, the value tested is 0, which means it's completely short-circuited. Remove the MacBook Pro motherboard, and then use to remove the damaged capacitor, and then measure it again with digital multimeter, now the resistance value measures is 350ohm, which is normal. Next we need to find a same capacitor and install it to the MacBook motherboard, and then assemble the MacBook Pro. Supply power to it, press the power button, the fan turns normally, and then the MacBook Pro screen also displays properly. After entering the system, all functions tested are normal. The MacBook Pro has been repaired!

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How to Fix MacBook Air A1466 Boot Failure After pressing the MacBook power button, it has no response, but there is the charge power when connect it to the DC power supply, what causes MacBook has boot failure? The model for this MacBook is A1466, the motherboard model is 820-00165A, which is released in 2015. How to fix MacBook boot failure? Get solution here! Because the MacBook Air doesn't respond to booting, when connect it to the power supply, it has charge current, so now we need to check MacBook motherboard. Carefully remove the MacBook rear case, disconnect the MacBook battery, and then connect it to the DC power supply to measure the current. The current up to 0.3 and then directly falls to stand-by current 0.03, when we press the power button again, the MacBook has no response, which means the MacBook motherboard disconnect power for protecting. Check the bottom of the MacBook motherboard, no obvious traces of water or damaged were found. Remove the MacBook motherboard directly, there is an obviously traces of water on the back side of the motherboard, and there is a corrosion phenomenon.

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Macbook Repair Guide Repair Case v1 Clean the water traces on the MacBook motherboard with PCB cleaner, and then check MacBook schematic diagram and boardview, so we can know the specific model of the corroded chip.

After checking the MacBook boardview, we know that it's a U1950, it's the circuit for 8 Pin, it controls the generation of PM_PCH_SYS_POWER. In chronological terms, if there is a problem with this signal, then it can cause problems with both the clock and the reset. The current up to 0.3 and then fall off, maybe it's because U1950 damage caused PG to have a problem, we can remove this IC to check. Use hot air rework station to heat this IC, and then use tweezers to remove it. After removing, we found the solder pad is completely blackened, and it's clearly see that these is a solder pad are dropped. Open the MacBook boardview to check, the 8 Pin is disconnected.

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Macbook Repair Guide Repair Case v1 This pin is the power supply pin for U1950, if this pin is disconnected, then this circuit must not work. Clean the solder pad, and then connect wire for 8 Pin, and then install the chip.

Now, assemble the MacBook air, press the power button, the MacBook is turning on smoothly. After entering the system, test the keyboard, trackpad and charge function for MacBook, they all work properly. The A1466 MacBook failure has been fixed!

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Part-3 Troubleshoot MacBook won't Turn on

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MacBook Pro won't Turn on (Damaged Resistor) The model for this MacBook is A1278, the motherboard model is 820-2936-B. Press the power button on the MacBook and it is not responding, this MacBook Pro won't turn on. How to solve this problem?

Connect the MacBook Pro to a DC power supply, there is a charge current, press the power button on the MacBook Pro, the MacBook screen doesn't display, it won't turn on. Disassemble the MacBook Pro, remove the MacBook rear case, and disconnect the MacBook battery. Supply power to MacBook, the current rises to 0.27 and then stops moving, so there should be a power supply that doesn't output successfully. Carefully remove the MacBook motherboard, we can see that there are several components have been repaired.

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The MacBook Pro charging IC has been welded, and a small component next to it has been lost. View the MacBook schematic diagram and viewboard. Check schematic diagram and boardview. Click here for download schematic diagram and boardview.

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Macbook Repair Guide Repair Case v1 After observation, we found the Q9425 Mosfet tube is not installed, which is a tube to control HV power supply, if this tube is not installed, then it will cause HV lightning interface can't be used.

Keep checking, we found the PP1V05_S0 control IC U7600 also has been welded.

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Macbook Repair Guide Repair Case v1 And U4900 EC IC also has been welded, in a word there are a lot of repaired marks on the MacBook motherboard. Supply power the MacBook motherboard, and then use digital multimeter to measure the voltage for each inductor, when measured to the inductor next to the MacBook Pro CPU, it has no voltage.

According to the MacBook schematic diagram, this inductor is L7510. L7510 is the CPU core power supply inductor, which is controlled by U7400 and then output the voltage.

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Macbook Repair Guide Repair Case v1 Measure the working condition for U7400, the power supply for 15 Pin 20 Pin 40 Pin all is 5V, which is normal, measuring 1 Pin CPUIMVP_VR_ON voltage is 3.3V, it's normal. Measuring 18 Pin CPU_VIDSCLK voltage is 1.05V, it's normal, measuring 16 Pin CPU_VIDSOUT voltage is O.9V, while the normal voltage should be 1.05V, which is abnormal.

CPU_VIDSOUT is passed through the resistor R7480, and then provides the pull-up by the PP1V05_SO, find the resistor R7480 on the boardview.

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The resistor R7480 is under the radiator, remove the radiator to find the resistor, we can clearly see that the resistor is blackened, so use hot air rework station and tweezers to replace the resistor directly. After replacement, supply power to the MacBook motherboard, now the current displays normally. Next measure the voltage for CPU_VIDSOUT, its 1.05V, which also is normal. Install the MacBook Pro, press the power button, now the MacBook Pro can be displayed properly, and it access to the system successfully.

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MacBook Air A1466 won't Turn on Here is an A1466 MacBook Air with boot failure, the motherboard model is 820-3437B. Supply power to the MacBook Air, the green light lights up smoothly, and then press the MacBook power button, the MacBook doesn't response to it. In a word, the MacBook Air won't turn on. Here we can get the solution. Disassemble the MacBook Air, remove the MacBook rear case, and then remove the MacBook motherboard. It's clearly see that the MacBook Air was repaired before, there are several places where the solder paste is not disposed of clean, and the BIOS chip was disassembled before.

First we need to clean up the solder paste. Use PCB cleaner and Brush to clean the MacBook motherboard, and then we need to check MacBook schematic diagram and boardview. Click here for download schematic diagram and boardview. Check MacBook schematic diagram and boardview, and then use digital multimeter to measure the related components on the MacBook motherboard. Measuring the P7095 PP3V42_G3H, it's 3.42V, which is normal. Measuring the L7560 PP3V3_S5_REG_R, the data measured is 3.3V, which is normal. Measuring L7130 PPBUS_G3H, the data measured is 8.2V, which is normal. Connect the MacBook Air to power supply, and install the MacBook battery, the MacBook Air doesn't trigger automatically, but the charge current is normal, SMC_ONOFF_L has 3.3V.

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Pull down the SMC_ONOFF_L manually, the current jumps as usual, which means it's not the problem of the switch circuit. Use digital mulitmeter to measure the EC power supply, it's normal, the reset signal also is normal. Then use oscilloscope to measure the clock crystal vibration waveform, it's normal, and the SMC_LID also is normal. The working condition for the EC is normal. As we know, if the MacBook want to trigger smoothly, then in the PCH inside the CPU, it have to receive the RSMRST* signal first, so we can follow this signal to check the reason.

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Search the PM_RSMRST_L on the schematic diagram, and then measure the voltage of the PM_RSMRST_L to check whether it's normal.

Measure the voltage for the U8130 6 Pin, it's 0V, which means there is no voltage on the PM_RSMRST_L. Disconnect the power first, and then measure the grounding resistance value for 6 pin, the resistance value is normal. Next we need to check the working condition for U8130. After measurement, the U8130 power supply 1 Pin VDD is 3.3V, which is normal, while 2 pin SENSE is 0V, which is abnormal. The outside of the SENSE is supplied by PP3V3_SUS, check schematic diagram, we can see that it was converted from U8020.

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The voltage of U8020 VIN Pin is 3.3V, it's normal, we can measure the ON pin voltage by capacitor C8020, it's 0V, search the P3V3SUS_EN signal, the source was renamed by PM_SLP_SUS_L through the resistor R8190. Measuring R8190, both sides of the voltage is 0, which means there is a problem with PM_SLP_SUS_L signal. PM_SLP_SUS_L signal is directly outputted by U0500 CPU, so now we need to check the standby condition of the CPU. After measurement, the CPU standby condition power supply PPVRTC_G3H is 3.3V, it's normal, the clock PCH_CLK32K_RTCX1 RTC clock is normal, the signal VCCDSW3_3 deep sleep voltage is 3.3V, which is normal, the PM_DSW_PWRGD deep sleep voltage is 3.3V, which also is normal. Now we need to measure the PCH_DSWVRMEN voltage of the pull-up supplied by PPVRTC_G3H, the normal voltage for DSWVRMEN should be 3.3V, while the real voltage for PCH_DSWVRMEN only about 1V, this voltage is mainly supplied by PPVRTC_G3H, but the voltage of the PPVRTC_G3H is 3.3V, it's normal. So, now we suspect that the R145O resistor has some problems. Use digital multimeter to measure the resistor R1450, the data is around 2M, while the normal data is 330K, it's abnormal.

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Use hot air rework station to remove the R1450, and then install the new R1450. After replacement, supply power to it, now the current jumps normally. Install the MacBook Air, press the power button, the MacBook is turned on smoothly.

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MacBook Pro 13 A1708 Won't Turn On Here is a 13-inch MacBook Pro with won't turn on problem, the fault described is that the MacBook Pro display screen suddenly turns black during the normal use, after pressing the power button, it has no response, the MacBook Pro 13 A1708 won't turn on anymore. Luckily, here is a solution to fix it. Firstly, connect MacBook Pro to the power supply via Apple lightning cable, press the power supply on MacBook, the MacBook has no response, it keeps black. Disconnect the power supply, open the MacBook, remove the rear case, and then remove the MacBook battery. Now carefully remove the MacBook motherboard. After taking out the MacBook motherboard, we can smell a charred smell, we suspected that there are some components had been burned. We need to find out the damaged components, put MacBook Pro to the WL Aluminum Alloy Pad.

Check schematic diagram and boardview, there is a compound diode D6905, which is for generating PP3V3_G3H, the first 3.3V power supply.

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Based on MacBook schematic diagram, we know that the L6995 and D6905 inductors are related to this circuit. Use digital multimeter to measure the inductor L6995, the value tested is 342, which is normal.

Next, we need to measure the inductor D6905, there are 3 pins we need to measure, they were pin 1, pin 2 and pin 3. After measurement, only the value of pin 2 is tested normally, both pin 1 and pin 3 are abnormal. The pin 1 value tested is 97, and the pin 3 value tested is 0, which is shorted.

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We need to remove the D6905. Put MacBook motherboard under the microscope, with the help of hot air rework station and tweezers, we removed the D6905 smoothly. Now, we need to measure the pin 1 and pin 3 again. The value of the pin 1 is 442, which is normal, but the value of pin 3 is 0, which is still shorted. Check the MacBook schematic diagram again, we can see that the pin 3 of D6905 is connected to pin 2 of U6990.

Use hot air rework station to remove the U6990, and then use digital multimeter to measure the pin 3 of D6905 again, the value tested is 0, it's still shorted. What's the real problem? We need to check schematic diagram, at this time, we noticed that pin 3 of D6905 also is connected to C6990 and C6991. Remove these 2 capacitors, and then measure the pin 3 again, now the data tested is normal.

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Now, install the new U6990/D6905/C6990/C6991 back to the MacBook motherboard, after installation, use digital multimeter to test MacBook motherboard, all data tested are normal. Assemble the MacBook, supply power to it, press the MacBook power button, after few seconds, the MacBook is turned on properly. Using it for a while, the MacBook display screen works normally, and other functions also works perfectly.

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MacBook Air A1369 won't Turn on (no power light) Power the MacBook Air and press the power button as usual, the power light doesn't turn green, and the MacBook air doesn't turn on. When we press the power button on MacBook Air, there is no boot ringtone, the power light and MacBook display screen are black, in a word, and the MacBook Air doesn't react to this startup operation. We need to fix this problem, here is the troubleshooting solution.

The model for this MacBook Air is A1369 and the motherboard model is 820-3023-A. Connect the MacBook Air to a DC power supply to test the current, after measurement, the standby current only has 0.03, which is abnormal. Based on our repair experience, first we should try to fix this problem by replacing power board and flex cable.

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Macbook Repair Guide Repair Case v1 After replacing the power board and flex cable, power the MacBook, the failure is still the same, the green light didn't light up and the MacBook Air doesn't turn on. Remove the MacBook motherboard to see if there is significant water damage or other damage to the motherboard, after observation, no traces of water were found on the motherboard. Connect the power board, power it, and the measure the standby voltage. When connect it to the power, the green light is on, and the current has jumped, too. The MacBook Air motherboard can be turned on, which means that there should be a problem with the external accessory, which causes the failure. Install the motherboard back the MacBook Air, and then install an external accessory, power it to test, when installed a trackpad flex cable, it's found that the green light is off.

Disassemble the MacBook battery, disconnect the keyboard, power the MacBook Air, the green light is on.

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Macbook Repair Guide Repair Case v1 According to this situation, we confirmed that the MacBook keyboard itself is damaged, and then it causes the green light doesn't light up and then MacBook Air doesn't boot. Now we need to replace it with the new keyboard. Carefully remove the damaged keyboard, and then install a new keyboard.

After replacement, power the MacBook Air, the green light is on, the charge current is normal, and the MacBook Air access to the system properly.

Test the keyboard on the MacBook Air, the trackpad and WIFI all are normal, the trouble has been solved!

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MacBook A1466 Green Power Light not Lit When the A1466 MacBook Air is connected to the power supply, the MacBook Air power light is not lit. Press the power button, the MacBook Air has no reaction to this, which means the MacBook Air doesn't boot. The motherboard model for this MacBook Air is 820-3437-B, it's with 13-inch screen. What's the trouble with this MacBook Air? Use screwdrivers to remove the screws that fixing the MacBook Air rear case, and then remove the MacBook rear case. Disconnect the MacBook Air battery, and then remove the MacBook Air motherboard. Observing the MacBook motherboard to view if it has water traces, after observation, the MacBook motherboard has no visible traces of water.

Check MacBook schematic diagram and boardview.

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As we know, in general, there are two reasons why the MacBook green light is not lit: - Damaged EC chip - The problem with the working condition for the EC chip, in resulting the problem with EC chip detection power supply Now let's start to measure the power supply and grounding resistance for the MacBook motherboard. Measuring the first stand-by power supply L7095 PP3V42_G3H by digital multimeter.

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Macbook Repair Guide Repair Case v1 After measurement, its voltage is 2.5V, which is abnormal, because the normal value is 3.42V. It seems that the power green light won't light up because of this low voltage. Therefore, we need to check the working condition for this chip.

According to the schematic diagram, we know it's a small PMW chip, it's internally integrated with up and down MOS tubes. It's powered by 6 Pin VIN, 8 Pin SHDN is the opening of the chip, 4 Pin controls inductor L7095 to produce the voltage, 1 Pin and 2 Pin are voltage feedback, 5 Pin 9 Pin are grounded Pins. Generally, there are 3 reasons that can cause low voltages: - The problem with the voltage feedback - The problem with the chip itself - The problem with the capacitor

So now we need to measure the resistance values for Ra and Rb these 2 resistors. Use digital multimeter to measure the resistance value for these 2 resistors, the resistance value for R7095 measured is normal, and the resistance value for the R7096 measured also is normal, which means the feedback resistor has no problem. Now we need to try to fix by replacing the chip. Use hot air rework station and Titanium Alloy Tweezers to remove the U7090, and then install the new one. After cooling the motherboard, supply power to measure

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Macbook Repair Guide Repair Case v1 the voltage, the voltage tested is still about 2.5V, it seems it's not the problem of the chip. After excluding the problem of the chip and feedback resistor, now we need to check filter capacitor.

These 2 capacitors are easy to damage, use hot air rework station to replace these 2 capacitors. After replacement, supply power to the motherboard to test, now the power green light is lit up. Use digital multimeter to measure it, now the voltage is 3.42V, which is normal, and then current jumps also is normal. Assemble the MacBook Air and test it, everything is alright.

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MacBook Pro A1502 won't Turn On (CPU Shortcircuit) An MacBook Pro won't turn on, because the MacBook Pro CPU is damaged, the MacBook CPU is short-circuited, we need to fix it by replacing the MacBook CPU. The model for this MacBook Pro is A1502, the motherboard model is 820-4924-A. First of all, test the MacBook Pro. Press the MacBook Pro power button, the MacBook Pro has no response, the MacBook Pro won't turn on. Connect it to the power supply to check the current, there is the charge current. Disconnect the power supply, we need to disconnect the MacBook Pro battery. Use screwdrivers to remove the screws that fix the rear case of the MacBook, and then remove the MacBook Pro rear case. Disconnect the MacBook Pro battery, and then connect MacBook Pro to the external power supply via Apple lightning cable, we can see that the current jumps from 0.03 to 0.05. Based on the current tested, we know that the MacBook Pro has a trigger action. Next remove the MacBook motherboard, and then check MacBook motherboard carefully to see if there is a obviously water-damaged trace or damaged components, there are no obviously failures. Use digital multimeter to measure the grounding resistance value for each inductor on the motherboard, when measuring a inductor on the MacBook CPU, the grounding resistance value is 0Ohm, which is abnormal.

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Check the MacBook schematic diagram and boardview, we can see that this inductor is PP1V05_S0_REG, which is power supply inductor.

Now first we need to use soldering iron to pry up the inductor, and then use digital multimeter to measure it. After measurement, we found that the inductor 2 pin rear pole is short-circuited.

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Connect an external voltage to the inductor rear pole, the voltage can't more than 1.05V.

After powering up for a while, touch the MacBook Pro CPU with hand, we can feel that the MacBook CPU PCH part is overheat, now we can confirm that the MacBook CPU is damaged, in resulting the inductor L7630 short-circuited.

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Macbook Repair Guide Repair Case v1 Protect the components around the MacBook CPU with heat resistance tape, and then use PHONEFIX 999D hot air rework station to heat the MacBook CPU, next use BGA removal tool to remove the MacBook CPU, finally install the new MacBook CPU.

After replacement, use digital multimeter to measure the inductor L7630 again, the grounding resistance value tested is about 100ohm, which is normal. Now we need to re-modify the ME on the BIOS data, after re-modification, supply power to the MacBook to check the current, the current jumps properly. Install the MacBook Pro motherboard and rear case, press the power button, the MacBook Pro can be displayed normally. After few seconds, the MacBook is entered the system smoothly. The MacBook Pro has been repaired!

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Part-4 Troubleshoot MacBook CPU Problem

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MacBook Air A1466 CPU Short-circuit After pressing the power button the MacBook Air, it won't turn on. Why this MacBook Air won't turn on? After checking, we found there is capacitor on the motherboard is damaged, and it causes MacBook CPU is short-circuited, so the MacBook won't turn on properly. The MacBook model A1466, the motherboard model is 820-3437-B.

Connect the MacBook Air to the power supply, press the power button, the MacBook has no response. Disassemble the MacBook Air. Use screwdrivers to remove the screws that fix the MacBook rear case. Disconnect the MacBook Air battery, connect the MacBook Air to the DC power supply, there is the current reaction for triggering, the current jumps at around 0.03 to 0.08, and then drops. Press the power button on the MacBook Air, the current is the same. Take off the MacBook Air motherboard and observe it, we can see it there are many dust on the motherboard surface, and there is no obvious sign of water.

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Next use digital multimer to measure the motherboard. Switch the digital multimeter to the diode mode, and then use it to measure the grounding resistance value for the each inductor. After measurement, it's found that the grounding resistance value for the inductor that next to the MacBook CPU is 0, which is abnormal, its short circuited. Check MacBook Air schematic diagram. Click here for download schematic diagram.

Based on the MacBook schematic diagram, we know it's the core power supply of the Macbook CPU, it's a power supply dedicated to the CPU chip, is it a short circuit inside the MacBook CPU? Carefully remove the heatsink above the MacBook CPU.

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Macbook Repair Guide Repair Case v1 Now we can clearly see that there are moldy marks under the MacBook CPU heatsink, it should be wet for a long time, which causes the motherboard to oxidize moldy.

Use Brush and PCB cleaner to clean the moldy place, and then use hot air rework station and tweezers to pry the inductor L7310. Connect MacBook motherboard to the DC power supply, external connect a voltage of about 1V, and then touch the motherboard with hand, after a while, we can feel that the C1083 capacitor next to the moldy area is overheated.

Use hot air rework station to remove the capacitor C1083, and then use digital multimeter to measure the grounding resistance value, now the value measured is around 20 ohm, which is normal.

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Install the MacBook Air, and then test it, now the MacBook Air can be turned on successfully. After entering the system, all functions tested are normal.

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Part-5 Troubleshoot MacBook Water Damage Problem

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MacBook A1466 won't Turn on after Water Damaged A MacBook accidentally fell into the water, after drying the water, but the MacBook won't turn on anymore. Connect the MacBook to the power supply, the power light isn't lit, press the MacBook power button, the MacBook didn't respond. The model of the MacBook is A1466, the motherboard model is 820-00165-A, it's MacBook Air with 13 inch screens, and it's released in 2015. After removing the motherboard, we found there are the traces of repairing, some chips aren't installed back after disassembling, and there are many solder paste on the motherboard surface. First clean up the solder paste on the motherboard, install which chips that are not installed. Connect the motherboard to the DC power supply, the green light lights up, but the MacBook wasn't triggered. The reason the power light isn't lit at first is that the U7090 and related components have been removed, resulting in problems with EC working conditions. Check MacBook Air schematic diagram and boardview. Click here for download schematic diagram and boardview.

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Macbook Repair Guide Repair Case v1 Now the green light can light up normally, but it doesn't trigger. After checking the motherboard, we know the EC chip has been replaced, now we're going to start with the timing. Open the MacBook Air schematic diagram to check the working condition for the U5000 EC, power supply, clock, reset, and then the programs itself. The power supply of the EC has VDDA, VDD, the measured data for the VBAT is 3.2V, it's normal, the voltage measured for the VDDC is 1.2V, it's normal.

Next we need to test the clock signal of the EC, measuring the 1 pin and 3 pin of the crystal Y5110 with an oscilloscope at the moment of powering, the data measured is 12 M, which is normal.

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Finally measure the reset voltage of the EC, SMC_RESET was converted from U5110. After measuring, the 5 Pin of the U5110 has 3.3V voltage, which means the reset of EC also is normal. Until now, we only can replace the EC to check if the it's the EC itself problem.

In order to replace this EC chip, we need to remove an EC chip from a same junk motherboard, the inside of the EC chip is with a program, and if a different EC is changed, the MacBook screen may not display even if the MacBook can be turned on. Remove EC chip by hot air rework station, and then reballing the EC chip that disassembled from junk motherboard, install it to the motherboard. Supply power to it to test, but it's still the same failure, the green light lights up, but the MacBook wasn't triggered, which means it's not the EC chip problem.

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According to the repair experience, is it the BIOS data problem? Remove the BIOS chip, use programmer to write an original factory BIOS data. Soldering it back the motherboard, and then connect it to the power supply, now the current jumps. Based on the DC power supply, we can see that the MacBook restarts for twice, now it should be displayed. Assemble the MacBook and test it, now it can be turned on smoothly, and the MacBook screen displays properly.

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MacBook Air keeps Restarting after Water Damaged? The MacBook Air was damaged by water, it doesn't boot anymore. Press the power button on MacBook Air, after a while, the MacBook Air screen won't light up as usual, and then it automatically restarts. The MacBook screen is 13inch, the MacBook model is A1466, and the MacBook motherboard model is 820-3437-B, which is released in 2014.How to fix this problem? First, test the MacBook Air again. Press the power button and it is not responding. Connect the MacBook to the power supply, the green light is on, but it's not charged, possibly it's because of the self-protection of the MacBook battery. Disassemble the MacBook Air, remove the rear case, disconnect the MacBook battery, and then connect the MacbBook to the DC power supply to check the current. The current jumps, but the MacBook still keeps restarting. Disconnect the power supply, remove the MacBook motherboard. After checking the both side of the MacBook motherboard, we found there are the traces of the water, but it's not obvious. Check MacBook schematic diagram and boardview. Click here for download schematic diagram and boardview. Supply power to the MacBook motherboard, it restarts 2 times, and then the current returns to the standby status, it doesn't restart and doesn't trigger. Find the boot connector J4800 on the MacBook boardview.

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Use digital multimeter to measure the voltage for 20 Pin SMC_ONOFF_L, the voltage measured is 3.3V, it's normal. Short connect 20 Pin, but the MacBook still won't turn on. Now the problem becomes not to be triggered. As we know, if the MacBook needs to be triggered, the CPU must receive the RSMRST# signal, and then it emits a PWRBTN# signal to turn on the voltage after the trigger.

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Macbook Repair Guide Repair Case v1 Find the PM_RSMRST_L signal source on the MacBook schematic diagram, it's outputted from 6 Pin of the U8130.

Find the U8130 on the boardview, and then find it on the MacBook motherboard, we can see that the area around this chip has obviously traces of the water. Use digital multimeter to measure the voltage for the 3 Pin of the U8130 chip the current starts jumping, and then the MacBook restarts repeatedly, it seems the problem is here. The 1 Pin of the R8133 has obvious corrosion, use BGA remover blade to cut it.

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Macbook Repair Guide Repair Case v1 Now supply power to it, and then use digital multimeter to measure the 6 Pin of the chip again, the voltage jumps from 2V to 2.8V, and the MacBook keeps restarting. When measure the 1 Pin of the resistor, we found the resistor is disconnected, the voltage of resistor 1 Pin is 3.3V, it's normal. Perhaps this corrosion resistor causes the voltage transfer of this pull-up resistor to fail, causing voltage instability, and then causes the MacBook sometimes trigger and sometimes fail to trigger.

Use hot air rework station to replace the 100K resistor, after replacement, supply power to it, the MacBook motherboard restarts 2 times, and then it stops restart, the MacBook screen should be displayed. Install the MacBook Air, press the power button, after few seconds, the MacBook screen displays normally. After entering the systems, test those functions, the keyboard, trackpad and other functions all are normal, the problem has been fixed!

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MacBook Pro won't Turn on After Liquid Damaged A MacBook Pro won't turn on after liquid damaged, the model for this MacBook is A1502, and the motherboard model is 820-4924-B. The fault described is that some liquid unexpectedly into this MacBook Pro, and then the MacBook pro has no response after pressing the power button, even connect the MacBook Pro to power supply directly, it still doesn't boot. Now we are going to solve this problem. Firstly, connect the MacBook Pro to the power supply, press the MacBook power button, the current rises to 0.35 and then stop moving. According to the current status, we know that this MacBook Pro also won't charge. Perhaps it's the MacBook Pro battery is completely out of power, now it can only be charged after activation. Use screwdrivers to remove the screws that fix the rear case, and remove the MacBook rear case.

We can obviously see that this MacBook Pro is traces of liquid intrusion. Disconnect the MacBook battery, connect it to the power supply, the current value tested is the same as before, it rises to 0.35 and stop moving, which means that the MacBook Pro won't turn on problem is caused by MacBook Pro motherboard power supply. Remove the MacBook Pro motherboard.

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We can obviously see that the screen flex cable connector on the front of the MacBook motherboard is corroded. Check the back side of the MacBook motherboard, it's damaged by water seriously, there are 2 chips around that are moldy and blackened.

Check MacBook Pro schematic diagram and boardview to check oxidized chips. According to the MacBook schematic diagram, we know that it's the CPU power supply IC, check another oxidized chips.

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According to the MacBook schematic diagram, we know that it's the PP1V05_SO_REG.

First we need to clean up the oxidized chips with PCB cleaner, after dealing with the solder pad, find a junk motherboard, take off the useful components, and then replace all the damaged components on the MacBook Pro motherboard.

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After replacing the IC, make sure that the oxidation area isn't disconnected. Power-on to check the current, current up to 0.23 and then drop. Based on this situation, we suspected that there are some voltage doesn't works properly. Observing the MacBook motherboard carefully to check whether there is other water damaged area. We can see that there is a chip under the Nand flash that's obviously moldy, check MacBook schematic diagram and boardview.

It's PP1V8_S3_REG voltage supply, use digital multimeter to measure the inductor L7820, there is no voltage, and the resistors next to this IC is blackened.

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Resistor R8166 was supplied to ALL_SYS_PWRGD by P1V8S3_PG00D, if the resistor is damaged, then it will pull down ALL_SYS_PWRGD, in resulting the motherboard out of power. Directly replace the IC U7820 and resistor R8166. After replacement, connect it to the power, now the current jumps properly, so the MacBook Pro screen should be displayed. Install the MacBook Pro, supply power to it, the MacBook Pro screen is displayed, but no backlight, the screen is darkness. Now we need to check MacBook screen flex cable connector. It's obviously that the MacBook screen flex cable connector is been badly blackened.

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Macbook Repair Guide Repair Case v1 Check schematic diagram and boardview, it's 1 pin PPVOUT_SO_LCDBKLT, which is backlight power supply for the screen, use PCB cleaner and brush to clean the flex cable connector, we found the flex cable pin is damaged by oxidization.

Replace it with new flex cable connector, after handling the solder pad, install the MacBook Pro, supply power to it, the MacBook Pro screen backlight displayed properly. Entering the system to test the MacBook Pro keyboard and touch control board, all works well. The MacBook Pro has been repaired!

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Water-damaged MacBook Pro doesn't Display after Booting After powering the MacBook Pro, the MacBook Pro screen doesn't display. The fault described is that some water accidentally entered the interior of the MacBook Pro, after drying the water, we try power on MacBook, but the MacBook has no response, it keeps black. After checking, we found the current is normal, which means the MacBook Pro is turned on, we need to solve this MacBook screen problem. The model for this MacBook Pro is A1502, which is released in 2015, the MacBook motherboard model is 820-4924-A. Test the MacBook Pro. Press the MacBook Pro power button, the MacBook screen has no response, but we noticed that the MacBook fan runs properly. Disassemble the MacBook Pro. Use screwdrivers to remove the screws that fixed the rear case of the MacBook Pro, and then remove the MacBook Pro rear case. Disconnect the MacBook Pro battery, and then check current by DC power supply, the current jumps normally.

Carefully take off the MacBook Pro motherboard, we can see that the waterproof stickers on the MacBook Pro screen flex cable interface has turned red, and the MacBook Pro screen flex cable interface also has obvious signs of oxidation.

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We can obviously see that the MacBook Pro screen flex cable connector is damaged, after removing the screen flex cable connector, we saw that a lot of the solder pads under the screen flex cable connector were blackened.

First, use PCB cleaner to clean up the MacBook screen flex cable connector solder pad, and then use soldering iron to weld the low temperature solder wire on the solder pad. After welding, don't rush to install the screen flex cable connector. Next we use digital multimeter to measure the grounding resistance value for the screen flex cable connector.

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When measured the pin 1 for the screen flex cable connector, the resistance is infinitely large, which means it's disconnected. Check the MacBook schematic diagram.

After measuring, the screen flex cable connector to diode tube D7710 is disconnected.

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From the MacBook boardview, we can see that all of these pins are connected, it can be connected from capacitor C8300 pin 1 to connector pin 1.

After soldering the jump wire, we can install the new MacBook screen flex cable connector.

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After soldering the connector, use PCB cleaner to clean up the connector, and then use digital multimeter to measure the grounding resistance for each pins of the connector, all data tested are normal. Connect it to the MacBook display screen, and then supply power to it, the MacBook screen can be displayed properly.

Finally, assemble the MacBook Pro, power on it and test it, all functions tested are normal, the MacBook Pro has been repaired!

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Liquid-damaged MacBook Air CPU stops working A MacBook Air was damaged by liquid, the MacBook Air CPU stopped working, in resulting the MacBook Air won't turn on. The MacBook model is A1466, the motherboard model is 820-00165-A. Now we are going to fix it. First, test the MacBook Air. Press the MacBook power button, the MacBook Air didn't respond. Connect the MacBook to the external power supply, it doesn't charge. Now we are going to disassemble the MacBook. Use screwdriver to remove the screws that fix the MacBook Air rear case, and then remove the MacBook rear case. Disconnect the MacBook battery, supply power to it, the MacBook motherboard doesn't trigger, and there is the standby current, the MacBook power green light is also lit. Remove the MacBook motherboard, it's clearly see that the motherboard has the traces of the liquid. Check the front side of the MacBook Air motherboard, we can clearly see that the components next to the MacBook hard disk interface are severely damaged by liquids, there are many components are moldy.

Now we are going to check the back side of the MacBook motherboard, it also was severely damaged by liquids, it's clearly see that there are many components next to the EC chip are moldy.

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We need to use PCB cleaner and Brush to clean up the motherboard, cleaning all the moldy oxidized components, and then get the motherboard dry. After drying the motherboard, use DC power supply to test the motherboard, now the MacBook motherboard triggers automatically, the current up to 0.45 and then stop moving. Use digital multimeter to measure the voltage for each inductor, measuring the voltage for the U2071 4 Pin PLT_RST_BUF_L, the data measured is 3.3V, it's normal. The reset signal is normal, which mean the power supply, the clock and the reset for the motherboard all are normal.

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Macbook Repair Guide Repair Case v1 Next we need to measure the waveform of the LPC_AD to judge whether the CPU is working. After measurement, there is no waveform, only the voltage. Disconnect the power supply, use digital multimeter to measure the grounding resistance value for the LCP_AD, when measured the resistor R1540 1 Pin LPC_AD, the resistance value is 30ohm, which is abnormal. Measure the other resistors on the LPC_AD, the grounding resistance value is about 470ohm, all is normal.

Remove the resistor R1540, the 1 Pin resistance value of the resistor is 28ohm, the 2 pin resistance value is 460ohm, which means it's 1 pin are pulling down the resistance. Check MacBook schematic diagram, we can see that the resistor 1 Pin LPC_AD is directly connect to U5000 EC. Directly remove the EC chip, it's obviously see that the chip is blackened.

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Replace the new EC chip, we need to disassemble the EC chip from the same motherboard model. After replacement, supply power to the motherboard, now the current jumps normally. Assemble the MacBook Air and test it, the MacBook is turned on successfully. After testing functions, the MacBook keyboard doesn't work, we confirmed it's damaged by liquid, directly replace the new keyboard, now the MacBook Air is working perfectly.

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Water-damaged MacBook Pro A1706 13 inch Here is a water-damaged 13-inch MacBook Pro need to repair, the problem is that the MacBook enters system very slow, but the fan turns fast, we need to fix it. After observation, we know that the model for this MacBook Pro is 1706, which is released in 2016, the motherboard model is 820-00239-09. First of all, we need to test it. Press the MacBook Pro power button, the MacBook Pro displays normally, but it's slow to enter the system. Meanwhile, we can hear the fan inside the MacBook turns very fast. One more thing, we learned from the MacBook Pro owner that there is water coming into this MacBook Pro. Now, we are going to fix it. Power down the MacBook Pro, and then use screwdrivers to remove the screws that fixed the rear case of the MacBook, and then remove the rear case. Disconnect the MacBook Pro battery, and then connect it to an external power supply. Power on MacBook Pro, when the MacBook Pro enters the system halfway through, the fan began to turn fast, the MacBook Pro has to step for a long time to into the system. Disconnect the power, carefully observe the MacBook Pro, there is no obviously trace of water, when check the touch control board, obviously there is a problem, the waterproof sign on the touch control board turned red, and we still can see the water trace on the touch control board.

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Macbook Repair Guide Repair Case v1 Now we can use a new touch control board with flex cable to test it, if it's confirmed that it's the problem of the touch control board, and then we can remove the old touch control board from the MacBook. Connect the new touch control board, and supply power to the MacBook, press the power button, now the MacBook can enter the system quickly, the fan also runs properly, now we can confirmed that it's the problem of the touch control board that damaged by water. For this MacBook Pro, we can disassemble the touch control board without removing the battery, directly use screwdriver to remove those several screws fixed on it, and then we can take off the touch control board.

After disassembling the touch control board, we can see there is some liquid under the board, clear it up.

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Macbook Repair Guide Repair Case v1 Now install the new touch control board, and then assemble the MacBook Pro. Press the power button on MacBook, the MacBook is turned on smoothly, after entering the system, test the functions on MacBook, all works good. The repairs end!

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MacBook A1502 doesn't Boot after Water Damaged A MacBook Pro doesn't boot, there was water coming into the computer on one months ago, but the MacBook Pro still can be used for a month, however, now it can't be turned on, when you press the power button, the MacBook Pro doesn't respond, we suspected that the MacBook motherboard has been damaged by water, we need to fix it. The model for this MacBook Pro is A1502, the motherboard model is 820-3476-A, which is released 2013, with 13-inch LCD screen. Disassemble the rear case, disconnect the MacBook battery, and connect it to the DC power supply to test it, first we see the MacBook current is 0.02, after standby, and trigger it automatically, it stuck at 0.13. This current phenomenon is usually caused by a lack of voltage or low voltage, which causes the MacBook motherboard not to work. Disassemble the MacBook motherboard, check the front side of the motherboard, we didn't see any visible traces of water, check the rear side of the motherboard, also no visible traces of water.

Use digital multimeter to measure the voltage for each inductors, when measured inductor L7310, the value measured is 0V, which is abnormal. Check MacBook schematic diagram to find F7310, we know that this inductor is CPU core power supply, CPU power supply IC U7200, control U7310 through the upper and lower M0S tube, through the inductor L7310 and then produce PPVCC_SO_CPU.

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Macbook Repair Guide Repair Case v1 So, we're focused on checking the working conditions of the CPU power supply IC.

Measuring the main power supply 17 Pin VIN voltage, it's 12.9V, which is normal, 16 Pin VDD is 5V, which is normal, when measure open signal 1 Pin VR_0N, this is no voltage, that's the main reason that caused this IC doesn't work. This signal is directly outputted by F60 Pin of the U0500 CPU.

If the CPU want sent out the CPU_VR_EN, it needs receive the CPU_VCCST_PWRGD voltage first, and then can receive the B59 Pin.

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Measuring it with digital multimeter, it only has 0.5V, while the normal value is 1.05V, obviously the output has some problem. 1 Pin 3.3V is normal, 2 Pin ALL_SYS_PWRGD is 0V, so we need to check ALL_SYS_PWRGD. Check the source of the ALL_SYS_PWRGD on the schematic diagram.

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Macbook Repair Guide Repair Case v1 It's summed up by several PG, we can disconnect these capacitors and then measure the all _ sys _ PWRGD voltage to determine whether these PG pull low voltages or other reasons. Open the boardview, find R8169, R8165, R8164, R8168, R8162 respectively, disconnect these capacitors, and then measure it, it's found that each PG output are normal, it's 3.3.V, which means it's not pull low voltages by PG. Next check ALL_SYS_PWRGD.

According to the schematic diagram, we need to check protective tube Q8150. Find Q8150 on the motherboard, observe it under the microscope, it's moldy, possibly this damaged tube pulls down the voltage. Carefully remove this damaged tube, and then install the new one, after handling the solder pad, install those several capacitors back to the motherboard. Now measure it again, the current measured is normal. Assemble the MacBook Pro, press the power button, now the MacBook is turned on smoothly, the problem has been fixed!

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Part-6 Troubleshoot MacBook Restarts Problem

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MacBook Air A1370 Stuck in Restarting Loop Here is a repair case about A1370 MacBook Air, its problem is that the MacBook Air stuck in restarting loop, it won't turn on successfully, and it just keeps restarting. The MacBook Air has been fixed once, but the problem still there, it still won't turn on properly. The motherboard model of this MacBook Air is 820-3024-B, now we're going to DIY fix it. First test the MacBook Air. Press the power button and the MacBook Air screen is not responding. Connect it to the DC power supply check current and we found it's charging. Remove the rear case, disconnect the battery. Based on the current, we know that the MacBook Air restarts over and over again, the current rises to about 0.18 mA and then drops. Directly remove the MacBook motherboard and observe it. We can clearly see that the repair marks on the opposite side of the motherboard is more serious. BIOS chip has been welded, there are a lot of solder paste around it, i guess the BIOS chip was torn down and the data was refreshed. And there are many solder paste on the memory IC, some ICs or resistors are not installed, we're going to install those resistors that aren't installed back and then clean up the solder paste on the motherboard. Connect it to the DC power supply to test the current, it's still the same, the MacBook restarts repeatedly. Now we are going to use oscilloscope to judge whether this current problem is caused by voltage or signal part. Directly measure the CPU_RESET_L CPU reset voltage. Check 820-3024-B schematic diagram and boardview. Click here for download schematic diagram and boardview.

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The instantaneous voltage of the U2780 4 Pin can reach 1.05V, which means the CPU reset is normal. If the CPU reset is normal, then which means the power supply of the motherboard also is normal, so the current problem should be caused by the signal part of the motherboard. We can use oscilloscope to measure the waveform of the LPC_A bus to judge if the CPU works or not.

After measuring it by oscilloscope, we found the LPC_AD doesn't have the waveform, which means the operating conditions of the CPU have not yet been met.

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Use digital multimeter to measure the grounding resistance value of the BIOS chip, we found the resistance value of the 2 Pin only has 130 ohm, while the normal value is about 450 ohm, so it's abnormal. 2 Pin is the output pin of serial data, view MacBook schematic diagram to check the connection point of the signal. According to schematic diagram, we know it was renamed SPI_MISO via resistor R5123.

The another side is directly connect to inside of the PCH bridge, remove the resistor R5123, measure the grounding resistance value of the 1 Pin and 2 Pin, the 1 Pin resistance value is 480 ohm, 2 pin resistance value is 130ohm, which means the 2 Pin pulls down the resistance value. Use hot air rework station to remove the BIOS IC, the 2 Pin of the resistor is infinitely large, the BIOS IC pulls down the resistance value, and the BIOS IC is damaged.

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Replace the new BIOS IC, and then supply power to test it, the current rises to about 0.5, and then there's no jump, the CPU doesn't work. Is there a problem with the BIOS data? After re-flashing a BIOS data, the problem stills the same. This should be the original failure for this MacBook, the CPU doesn't work, the current raises to 0.5 and stop jumping. Use oscilloscope to measure LPC_FRAME_L signal to confirm the problem.

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Macbook Repair Guide Repair Case v1 After measurement, we found there is only high level voltage, no waveform, which means the PCH south bridge doesn't communicate with the EC, now we need to check the operating conditions for the PCH south bridge, mainly measure the power supply, clock and reset.

All of these measured are normal, now we confirmed it's the PCH itself problem, and it causes motherboard doesn't work. Use BGA soldering station to replace PCH. After the motherboard cools, supply power to check the current, now the current jumps normally. Measuring the LPC_FRAME_L wave form by oscilloscope, the waveform jumps properly. Assemble the MacBook Air, press the power button, now the MacBook Air is turned on successfully, the MacBook has been fixed!

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MacBook Pro Always Restarts Automatically When press the power button on MacBook, it has no response. The MacBook model is A1278, the motherboard model is 820-2836-A. After testing, we found the standby current is abnormal, this MacBook Pro automatically triggers and then restarts repeatedly. We need to fix it, here is a troubleshooting solution.

Use screwdrivers to remove the MacBook rear case, disconnect the MacBook battery, and then connect the MacBook Pro to a DC power supply. We can see that the current starts at 0.016 and when it increases to 0.777, it comes down. This MacBook Pro always restarts automatically.

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Macbook Repair Guide Repair Case v1 As we can see the standby current is abnormal, because the normal value should be 0.033, the value we measured is lower than normal value. Remove the MacBook motherboard to check whether the motherboard has obvious water traces or damaged components, after checking, we don't find any obvious faulty point. Check MacBook schematic diagram and boardview, find the charge inductor.

Use Oscilloscope to measure the waveform of the inductor L7030 1 Pin front side, the voltage only has 1.8V when it's in standby, which is abnormal.

And then it comes down to 1.8V, the current will comes down to 0.015, it's been looping like this. Check the MacBook schematic diagram, test the working condition of the charging IC.

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The voltage of 2 Pin measured is power voltage 16.5V, the voltage of 19 Pin and 20 Pin are 5V, the voltage of 3 Pin ACIN is 3.88V, they are normal. Disconnect the power supply, next use digital multimeter to measure the grounding resistance value of 17 Pin and 18 Pin battery charge current detection, the grounding resistance value of the 17 Pin CHGR_CSO_N measured is 545 Ohm, and the grounding resistance value of 18 Pin CHGR_CSO_P measured is 437Ohm. The grounding resistance value of these 2 Pin is different, while they should be the same, which is abnormal. Now measure the resistance between the two Pin, its 247 Ohm, which is abnormal.

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These 2 Pins are connected via low resistor R7050, so they should be connected. Now we need to measure the resistance value for R7051 and R7052, they were 1Ohm and 973Ohm. The resistance value of the R7052 is abnormal, because the normal value should be 0Ohm, we need to replace the resistor R7052.

Use hot air rework station and tweezers to remove the replace the R7052, after replacement, measure the resistance between 17 Pin and 18 Pin, now the value measured is 1Ohm, which is normal. Supply power to the motherboard, the standby current is back to 0.033, the motherboard is automatically triggered, and the current jumps normally. Assemble the MacBook Pro, and test it, now the MacBook screen displays normally, and it can enter the system smoothly.

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MacBook Air A1465 Restarts Repeatedly Here is a MacBook Air, it restarts repeatedly. The model for this MacBook Air is A1465, the motherboard model is 820-3435-A. After pressing the MacBook power button, the MacBook Air didn't respond. Supply power to MacBook Air, the MacBook Air charges normally. Then why MacBook Air keeps restarting? We need to fix this problem. Disassemble the MacBook Air, remove the rear case, disconnect the MacBook battery and then turn on the MacBook again, but it still doesn't respond.

Measure it by DC power supply, the current goes to 0.185 and then drops off, the MacBook Air restarts repeatedly. Obviously, there is a problem with the MacBook motherboard power supply, it should be caused by voltage loss or signal loss.

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Macbook Repair Guide Repair Case v1 Remove the MacBook motherboard, supply power to the motherboard, the current is still the same. Disconnect the power supply, carefully observe whether the motherboard has obvious water traces, or obvious damaged IC. When observed the opposite side of the motherboard, there are obvious corrosion traces.

Check schematic diagram. From the schematic diagram, we know it's a 24M crystal vibration of CPU. The CPU emits PCH_CLK24M_XTALOUT through Y1915 to generate 24M of clock through the covariant resistor capacitor, PCH_CLK24M_XIALIN is sent to XTAL24_IN Pin of the CPU. Open the MacBook Pro schematic diagram and boardview. Click here for download schematic diagram and boardview.

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Macbook Repair Guide Repair Case v1 This clock produces the premise that the motherboard power supply must be in a normal state, the CPU received the power signal, issued a PCH_CLK24M_XTALOUT voltage, then generate 24M clock. If this clock isn't generated, then the working conditions of the CPU will not be normal, and then it will not generate each clock. Use PCB cleaner to clean the solder board, and then use hot air rework station and tweezers to replace the corroded inductor and capacitor.

After replacement, cooling motherboard, and then measure the motherboard by DC power supply. Supply power to it to check the current, but it's still the same failure, the current is small, and it restarts repeatedly, which means these are other problems. Observe the corroded area on MacBook motherboard under the microscope, there are some solder pads are broken, which means there are problem with some connection points. Use digital multimeter to measure it, it's found the 2 Pin of the inductor R1915 and the 1 Pin of the inductor R1916 are abnormal, which means this point is disconnected. Continue to measure it, we found the 3 Pin of the crystal vibration Y1915 and 2 Pin of the capacitor C1916 also are abnormal, which mean this connection point also is disconnected.

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Macbook Repair Guide Repair Case v1 These 2 connections points are disconnected, which means the crystal vibration Y1915 is not working. Use solder wire to connect them, after connection, supply power to test it, now the current jumps normally.

Assemble the MacBook Air, press the power button, the MacBook screen displays properly. Continue to test other functions, the charge function, keyboard, trackpad and WIFI function all are normal, the MacBook has been repaired!

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MacBook Air A1466 820-3437-A Restarts Repeatedly Here is an A1466 MacBook with restarting problem, the MacBook Air restarts repeatedly. The MacBook motherboard model is 820-3437-A. Connect the MacBook to power supply, it charges normally. Press the MacBook power button, the MacBook doesn't boot. Remove the rear case, disconnect the MacBook battery, connect the MacBook to the DC power supply, the current rises from 0.02 to 0.22 and then falls off. Sometimes it rises to 0.17, and then falls off, the MacBook restarts repeatedly like this.

Disconnect the connection to the power supply, remove the MacBook motherboard. Carefully observe the MacBook motherboard carefully to check if there are traces of water or damaged components, after observation, we don't find any obvious faulty point. Adjust the digital multimeter to diode mode, and then use digital multimeter to measure the diode data for each inductors, all data measured is normal. Supply power to it, use oscilloscope to measure the voltage for each inductor. First measure the core power supply inductor of the MacBook CPU, measuring the waveform of inductor L7319 front end with oscilloscope, the waveform is normal, and the output voltage is 1.6V.

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The CPU core power supply is normal, next we need to check MacBook motherboard PG signal.

Measuring the 2 Pin PM_PCH_SYS_PWROK of the inductor R1962, this instantly outputs 3.3 V and then falls quickly.

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Macbook Repair Guide Repair Case v1 The PG signal is normal, next we need to check the clock of the motherboard. Use oscilloscope to measure the 24M clock of the CPU. Check MacBook schematic diagram, we know that 24M clock is generated by the crystal Y1915 through the covariant capacitor and the vibration resistor.

Use oscilloscope to measure the crystal vibration 1 Pin, it only has voltage, but there's no clock frequency. When measure crystal vibration 3 Pin, the current rises to 0.3 and won't drops off. Therefore, the problem may be in the crystal vibration. Remove the covariant capacitor and vibration resistor directly by hot air rework station, after replacement, supply power to it, and then use oscilloscope to measure the frequency for the crystal vibration 1 Pin and 3 Pin. Now the clock 24M frequency output is normal, and the current also jumps properly.

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Assemble the MacBook Air, connect it to the power supply, press the power button, the MacBook is turned on successfully. After entering the system, test the functions of the MacBook, they all works properly.

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MacBook Pro doesn't enter the System and Auto Restarts Here is a MacBook Pro doesn't enter the system, when we press the MacBook power button, it restarts automatically. It's stuck in this cycle, in resulting the MacBook Pro can't be used. This MacBook Pro with 13 inch display screen, the MacBook model is A1425, the motherboard model is 820-3462-A. We need to solve this problem. Firstly, test the MacBook Pro. Press the MacBook power button, it restarts automatically. Connect the MacBook Pro to the power supply, the MacBook Pro powered on automatically, but the MacBook display screen shows icons that are not allowed to enter the system.

Press the power button to try to turn it off, but the MacBook will not turn off, and it will restart. So far, there are two problems with this computer, one is that the MacBook doesn't enter the system, and the other is that the MacBook will restart automatically instead of a hard shutdown. Now we need to check whether it's caused by the keyboard, first disconnect the connection between the motherboard and keyboard, and then install a new keyboard, supply power to it, but the problem is still the same, it failed to hard shutdown, and it restarts, which means this problem is not caused by the keyboard.

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Macbook Repair Guide Repair Case v1 Disassemble the MacBook Pro, remove the MacBook motherboard. Observe MacBook motherboard carefully to check if there are obvious water traces or faulty point. After observation, we found that there was no water or obvious point of failure on the motherboard. Next we need to analyze it, what can cause these two problems? Check MacBook schematic diagram and boardview.

The MacBook displays normally, which means the power supply of the motherboard is good, so perhaps it's the problem with the signal or main control IC performance. As we know, there are many reasons why the MacBook can't be hard shutdown, the EC, PCH, BIOS data, external configuration, or the problems with external settings. Hard shutdown is pulled down an open signal, and then turn off the MacBook.

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Macbook Repair Guide Repair Case v1 According to the schematic diagram, we can see that PM_SLP_S5_L is sent out by U1800 PCH, PM_SLP_S5_L sent to U49000 EC. After EC received this signal with low level, it will close the rear voltage until the MacBook shutdown. Measure the PM_SLP_S5_L signal to check if it's pulled down when press the power button, PM_SLP_S5_L also comes to 2 Pin of the U7970.

Open the schematic diagram and boardview, find out the keyboard interface on the motherboard. From the boardview, we know that the switch signal SMC_ONOFF_L connect to a capacitor C5710, it can be short-connected capacitor directly to finish the hard shutdown.

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Macbook Repair Guide Repair Case v1 Use digital multimeter to measure the 2 Pin of the U7970, and use hot air rework station to short connect the capacitor C5710 to check whether the PM_SLP_S5_L signal was pulled down. After measurement, PM_SLP_S5_L voltage pulls down instantly, and then it goes back to the high level, which means PCH board can't receive the voltage of the PM_SLP_S5_L, in resulting the MacBook Pro restarts automatically instead of hard shutdown. Based on this situation, we know it's the problem with the PCH itself or EC. Try to fix it by replacing EC, disassembled an EC IC from the same model junk motherboard. Reballing the EC IC, then use hot air rework station to solder the IC backs to the motherboard.

After the motherboard cools, supply power to motherboard to test it, short-connect the capacitor C5710, now the current backs to the standby current 0.032, and it stops restarting. Install the MacBook, press the power button, after few seconds, MacBook Pro runs smoothly into the system. Test the keyboard and trackpad, they all work properly, and the charge function also works perfectly.

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MacBook Air A1466 820-00165-A Keeps Restarting Here is a MacBook Air with a boot failure, it keeps restarting. The MacBook Air automatically restarts in normal use, but it didn't restart successfully. When we hear the MacBook boot ringtone, it automatically restarts and falls into a loop. In a word, this MacBook Air keeps restarting, and won't enter the system successfully, how to fix it? The MacBook model is A1466, which is released in 2015. The motherboard model is 820-00165-A, the screen is 13 inch. According to the fault description, it's possibly caused by CPU, BIOS program or external configuration, we can use the exclusion method to fix this problem. Firstly, we need to disassemble the MacBook Air. Use screwdrivers to remove the screws that fix the MacBook rear case, and then we can remove the MacBook rear case. Disconnect the MacBook battery, and connect it with the power supply to test it, the problem still the same, the MacBook Air keeps restarting when the white screen and boot ringtone appears. Remove the MacBook Air motherboard to check whether there is water damaged, after checking, there is no obvious faulty point, now we're going to check the external configuration one by one. Disconnect the flex cable between MacBook keyboard and trackpad, and then supply power to the MacBook, however, the problem still the same, which means the boot failure, is not caused by MacBook keyboard and trackpad.

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Macbook Repair Guide Repair Case v1 Remove the MacBook camera flex cable, and the supply power to the MacBook Air to test it, but it's still same failure, which means it's not caused by MacBook Air camera.

Check MacBook schematic diagram and boardview, we can see that there is a voice circuit module on the power small board, directly take a new power small board to replace it. After replacement, supply power to it for testing, same failure, which means it's not caused by voice circuit.

Now, we need to check SSD and WIFI card. Remove the SSD first, and then supply power to MacBook Air to test, the failure still the same, which means it's not caused by SSD.

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Macbook Repair Guide Repair Case v1 Remove the WIFI card, and then supply power to the MacBook Air, now we can hear the boot ringtone, and the MacBook Air doesn't restart anymore. The WIFI card is damaged and it causes MacBook keeps restarting.

Replace the new WIFI card, and then install the external configuration. Press the power button on MacBook, after a while, the MacBook enters systems successfully, the MacBook Air boot failure has been fixed!

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Part-7 Troubleshoot MacBook Display Problem

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MacBook Pro A1286 Displays Blue Screen The MacBook Pro turns on smoothly when press the power button, but the MacBook Pro displays a blue screen. We tried to restart the MacBook Pro again, but the MacBook Pro screen still displays blue. The model for this MacBook Pro is A1286, and the motherboard model is 820-2915-B. How to fix this blue screen problem? Use screwdrivers to open the MacBook rear case, disconnect the MacBook battery, re-install the screen flex cable, and then test the MacBook pro again, but the problem is the same, the MacBook screen still displays blue. Directly disassemble the MacBook motherboard, connect it with the test screen and screen flex cable to test, power it, the MacBook Pro screen still displays blue.

Now we've ruled out the problem with the screen flex cable and the screen, so we suspect it's the problem with the MacBook Pro graphics processor, we try to fix it by replacing the graphics processor IC. Fixing the MacBook Pro motherboard on the BGA soldering station, the opposite side of the graphics processor is the graphics memory IC, we need to apply some high temperature resistance tape to the MacBook graphics memory IC and MacBook Pro CPU to protect them from the heat damage.

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Controlling the BGA soldering station, when the temperature of the motherboard reaches the predetermined value, the tin balls of the graphics processor IC solder point will slowly melt, and when the tin balls melt, remove the graphics processor chip with tweezers.

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Macbook Repair Guide Repair Case v1 After the motherboard cools, remove the motherboard. Apple some solder paste to the MacBook graphics processor solder pad, and the weld the solder pad with low temperature tin, and then flatten the tin of the solder pad with a sucking tin wire. After handling the solder pad, clean up the solder pad with PCB cleaner, apply solder paste evenly to the motherboard, and then put the new graphics processor to the right position. Fixing the MacBook Pro motherboard on the BGA soldering station, then control the BGA soldering station temperature to weld the graphics processor. After the motherboard cools, remove the motherboard, and then install the radiator. Connect the motherboard with the screen flex cable and screen, power it, the screen display normally, and it enters Apple installation interface directly.

Disconnect the power supply, assemble the MacBook Pro, get into the system to test the motherboard, all functions tested are normal, the MacBook Pro blue screen problem has been fixed!

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MacBook Air Display Screen Failure after Booting This MacBook Air screen doesn't display images after booting, after repairing the image problem, the MacBook stuck on Apple logo and won't access to the systems. The model for this MacBook is A1466, the motherboard model is 820-3437-B. How to repair this problem? The repair process is as follow. Press the power button to turn on the MacBook, we can hear the boot ringtone, but MacBook screen has response, but no images.

Open the rear case of the MacBook, disconnect the battery, it's obvious that the MacBook motherboard has traces of liquid damage. Remove the MacBook motherboard, check the back opposite of the motherboard, the opposite side of the motherboard can also clearly see traces of damage to the liquid. Seems this failure is caused by the liquid, clean up the corroded place first, we can see that the area next to the BIOS chip is more corrosive.

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Use hot air rework station and tweezers to remove the corrosion resistor.

Next use BGA graver blade to scrape the corrosion solder pad to check if there is disconnection phenomenon.

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Macbook Repair Guide Repair Case v1 After checking, no apparent disconnection was found, we can assemble the MacBook to test it now. Supply power to it and boot it, the Apple logo appears normally on the MacBook air screen, but it stuck on Apple logo and won't enter the system. Measure it with DC power supply, the current doesn't jumps.

Disconnect the power supply, and turn it on again, the problem still the same, Macbook Air won't enter the system, it always stuck on Apple logo. After few minutes, the MacBook screen has become blurred.

For this MacBook Air, it won't display the Apple logo at the beginning, and now the Apple logo appears, but it won't enter the system and the screen is blurred. According to our repair experience, this problem generally is caused by memory or CPU.

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Macbook Repair Guide Repair Case v1 Re-check the MacBook motherboard, we see that there's a WIFI card that hasn't been torn down, is this caused by WIFI? Directly remove the WIFI card, observing the WIFI card carefully, it's obvious that there is a corrosion trace.

Connecting motherboard to external configurations, supply power to it, turn on MacBook, the Apple logo appears normally, the current jumps properly, and the MacBook Air boots smoothly. Replace the new WIFI card and install it to the motherboard, and then assemble the MacBook Air. Press the power button, the MacBook is turning on smoothly. After entering the system, test charge function, keyboard and WIFI function, they all work well. The MacBook Air has been repaired!

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MacBook Air A1466 no Backlight after Booting Press the power button on MacBook, the boot bell rang smoothly, after few seconds, we found the MacBook Air screen has no backlight, it's abnormal. After removing the MacBook Air screen problem, we need to check the motherboard. The model for this MacBook air is A1466, the motherboard model is 820-00165-A, and it’s released in 2015. Disassemble the MacBook Air, remove the rear case, and then remove the MacBook motherboard. Remove the top half of the MacBook (display screen part), and then connect the MacBook motherboard to the screen via screen flex cable. In order to repair the backlight circuit, it has to be connected to the screen, the MacBook motherboard has to recognize the screen, so the open signal will display smoothly.

Check MacBook schematic diagram and boardview to find the screen flex cable connector, and then check MacBook backlight power supply circuit. According to the MacBook schematic diagram, we know that the PPHV_SOSW_LCDBKLT is the screen backlight power supply, check the source of the PPHV_SOSW_LCDBKLT.

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Macbook Repair Guide Repair Case v1 It is controlled by backlight chip U7701, use digital multimeter to measure the voltage for the boost inductor L7701, it's 8.5V, which means there's no boost to the voltage.

Open the schematic diagram to measure the working condition for the U7701.

Measure the VIN voltage through capacitor C7710, the value is 5V, which it's normal. Measure the VDDIO voltage through capacitor C7711, the value is 3.3V, which it's normal. Measure the EN Pin voltage at the 2 Pin of the resistor R7731, the value is 2.8V, which it's normal. Measure the PWM Pin voltage at the 2 Pin of the resistor R7704, the value is 2.8V, which it's normal. Measure the SCLK voltage at the 2 Pin of the resistor R7753, the value is 3.3V, which it's normal.

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Macbook Repair Guide Repair Case v1 Measure the SDA voltage at the 2 Pin of the resistor R7757, the value is 3.3V, which it's normal. The working condition for the U7701 all is normal, now we try to fix it by replacing the U7701. Use tweezers to remove the U7701, handle the solder pad, and then install the new U7701 IC. After installation, cooling motherboard, and then connect it to the screen, supply power to it, but the screen still no backlight. Now, we confirmed it's not the problem of the U7701.

Is is caused by boost circuits? Open the MacBook schematic diagram to check boost circuits. The chip controls boost resistor L7701, passing the boost diode D7701, and supply power to the boost capacitor to produce the high voltage, and then supply power to the backlight.

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Macbook Repair Guide Repair Case v1 Supply power to it, use digital multimeter to measure the voltage for both sides of the diode D7701. The voltage at the end of A is 8.5V and the voltage at the K end is 2.7V. Is the rear pole circuit low? Disconnect the power, measure the grounding resistance of the K point, the data is normal. Now measures the diode, we found that the forward resistance of the diode was infinite, which is abnormal. After checking, it's found that the inside of the diode was penetrated. Use hot air rework station to remove the damage diode, and then replace the new one.

After the motherboard cools, connect the motherboard and screen, supply power to it, now the MacBook backlight is lighted. Measure the voltage of the diode K point, the value is 25V, which is normal.

Assemble the MacBook Air, turn on it, the MacBook Air is turned on smoothly. Test the all functions on MacBook, each functions works fine.

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MacBook Air A1466 Screen Backlight doesn't Work After booting the MacBook Air, it can display, but no backlight, what's trouble? How to fix it? The trouble described is that there is boot music when we turn on the MacBook Air, but the MacBook Air screen doesn’t display after booting, the MacBook was in normal use yesterday, the MacBook user thought it was the screen problem. However, after testing, the MacBook displays normally, just the MacBook Air backlight doesn't work. We need to fix it. The model for this MacBook air is A1466, the motherboard model is 820-00165-A, which is released in 2015. First we need to disassemble the MacBook Air. Use screwdriver to remove the screws that fix the rear case of the MacBook Air, and then remove the MacBook rear case. Disconnect the MacBook Air battery, there are no unusual marks on the front of the MacBook motherboard. The backlight circuit is on the back side of the motherboard, don't remove the motherboard first, because we need to check the MacBook screen first, so we can confirm if this is caused by a screen problem. Remove the MacBook display screen, and then connect it again, power on the MacBook, the MacBook screen can display normally, but still no backlight, now we confirmed that the backlight problem is not caused by the MacBook screen. Take off the MacBook motherboard to check the reverse side of the MacBook motherboard, it's found that there are visible traces of corrosion on the side of the backlight circuit.

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Check MacBook schematic diagram and boardview.

First use boardview to find the corroded resistor, there are 2 resistors, they were R7731 and R7715. Open the MacBook schematic diagram to find these 2 resistors.

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U7701 is backlight control IC, according to our experience, this IC is easy to damage. There are many MacBook that hasn't been damaged by water, but the backlight doesn't work, generally we can fix by replacing this U7701 IC. What's the function for these 2 resistors?

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Macbook Repair Guide Repair Case v1 Based on the schematic diagram, we can see that the effect of these two resistors is to split the pressure. They pass the PPVIN_SOSW_LCDBKLT through 200K, then split the pressure with the 100K resistor, and eventually send it to the U77001 EN Pin as the opening voltage of the chip. Therefore, if these 2 resistors don’t work, then the chip certainly doesn't work, we can replace these 2 resistors first.

With the help of hot air rework station and twezzers, we replaced them smoothly. After replacement, handle the corroded solder pad, and then install the MacBook Air. Finally, power on MacBook Air, the MacBook Air screen displays normally, and the backlight also works properly, the MacBook Air screen backlight problem has been fixed!

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Macbook Pro A1278 no Backlight This MacBook Pro has backlight failure. The MacBook screen doesn't seem to react after booting, it keeps black, but we can see the Apple LOGO when we use external lights to shine the MacBook Pro screen, which means the MacBook Pro can be displayed, just no backlight. The MacBook model is A1278, the motherboard model is 820-3115-B. There are several reasons can cause no backlight on the MacBook Pro: - MacBook Pro screen itself problem - MacBook Pro motherboard backlight boost problem - MacBook Pro screen flex cable is damaged - The MacBook Pro screen flex cable connector on the motherboard is damaged First of all, we need to disassemble the MacBook Pro, use screwdrivers to remove the rear case of the MacBook, disconnect the MacBook battery to check if there are obvious damaged marks next to the screen flex cable connector. After checking, the MacBook Pro screen flex cable doesn't have the obvious damaged marks. Check MacBook schematic diagram and boardview.

After checking, the MacBook Pro screen flex cable doesn't have the obvious damaged marks.

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Macbook Repair Guide Repair Case v1 Check MacBook schematic diagram and boardview.

Check the relevant circuits of the MacBook screen flex cable

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Macbook Repair Guide Repair Case v1 From the schematic diagram, we know that 21 Pin and 22 Pin PPVOUT_SW_LCDBKLT is backlight power supply, so now we mainly to check the voltage for this signal.

The U9701 IC controls a boost inductor L9701 and boost diode D9701, and recharge or discharge by through boost inductor, and it produces voltage to supply power to the backlight. Check the working condition of the U9701.

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Macbook Repair Guide Repair Case v1 Use digital multimeter to measure the power supply VIN via capacitor C9710 1 Pin, the voltage is 5V, which is normal. Measure C9711 1 Pin VDD10, the voltage is 3.3V, it's normal. Next we need to measure the voltage of the C9701 boot Pin EN, for measuring this voltage, we need to connect it to the screen, because only if the motherboard is identified to the screen will it generate a voltage.

PPBUS_SW_LCDBKLT_PWR passes through 2 resistors R9731 and R9715 to split voltage, the voltage measured is 3.1V, which is normal. Then measure LCD_BKLT_PWM brightness adjustment PWN signal, generally it's outputted by graphics processor IC, this MacBook Pro doesn't has the graphics processor IC, so it's outputted by MacBook PCH south bridge.

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Measure the resistor R9704 2 Pin, it has 3.3V, it's normal. The working condition for IC U9701 is fine, so we can directly remove the U9701. Use PHONEFIX 999D hot air rework station to remove the IC, apply some solder past to the new IC, and then install the new IC to the motherboard.

After the MacBook motherboard cools, install the external accessories, the MacBook Pro screen displays normally, the backlight lights up normally, the MacBook Pro backlight failure has been fixed!

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MacBook Pro A1286 doesn't Display after Booting Power the MacBook Pro, press the power button, we hear 3 beeps, but the MacBook Pro screen keeps black, it doesn't respond. The model of this MacBook Pro is A1286, and the motherboard model is 820-2850-A. The boot ringtone is normal, which means the MacBook can be turned on, now we need to check what causes this MacBook Pro screen doesn't display. Based on our repair experience, the MacBook has 3 beeps after pressing the power button is generally a memory problem, or it's caused by the MacBook memory power and MacBook control chip.

The memory for this A1286 MacBook Pro can be unplugged directly. Now we need to disassemble the MacBook. Use screwdrivers to remove the screws that fixed the MacBook rear case, and then remove the MacBook rear case, disconnect the MacBook battery. For this MacBook, it has two of memory, carefully clean the memory slot and memory. After loading a memory, the MacBook screen can be displayed normally, while the MacBook screen can't be displayed after two memories are installed.

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Macbook Repair Guide Repair Case v1 Take out the Macbook motherboard and observe it.

After observation, we see that both the front CPU and the display card of the motherboard have welded marks, and there's a lot of solder paste next to it, this Mac was repaired before. Attach the motherboard to soldering station, and then heat the MacBook CPU to remove it. After removing the MacBook CPU, use hot air gun to solder a sucking tin wire to the CPU solder pad.

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Macbook Repair Guide Repair Case v1 Now install the new MacBook CPU to the motherboard, after soldering, power it to test, install two memories, and then turn it on, now the MacBook Pro screen displays properly. Assemble the MacBook Pro and test it, all other functions tested are normal, the repairs ended!

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MacBook Pro A1278 Displays Blurred Screen This MacBook Pro displays normally, but it will crash and displays blurred screen when typing with a keyboard. The model of the MacBook Pro is A1278, the motherboard model is 820-311-B. Press the power button on the MacBook Pro, the MacBook pro displays as usual, and it enters system normally, when press the keyboard with the hand, the MacBook Pro will crash and shows blurred screen. As long as the MacBook Pro is subjected to external forces, there will be this failure. We need to solve this problem. Disassemble the MacBook rear case by screwdrivers, we saw there are several screws for fixing the motherboard are not installed, this is supposed to be the MacBook Pro that's been repaired.

This MacBook Pro is integrated graphics processor, there are several reasons can cause this blurred screen problem: - MacBook screen flex cable - MacBook CPU IC - MacBook memory - MacBook memory slot virtual welding

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Macbook Repair Guide Repair Case v1 First we need to check MacBook screen flex cable. After turned on the MacBook, and when the MacBook screen is displayed normally, press the MacBook Pro screen flex cable vigorously, the MacBook Pro screen displays normally. Re-plug the MacBook Pro screen flex cable, and the MacBook screen still displays normally, which means it's not the problem of the MacBook screen flex cable. Next we're going to replace the MacBook memory. There are 2 memories on this MacBook Pro, unplug the memory above first, power the MacBook Pro and enters system, press the keyboard, the MacBook Pro is crashed. Install the above memory, and unplug other memory, turn on MacBook Pro, and press the keyboard, the MacBook Pro is normal, no crashing or burred screen, this means that the problem is caused by the memory below. Replace it with the new memory, and install it to the slot below, power on the MacBook Pro, but the MacBook Pro is still crashed and the screen is blurred. Now we suspected it's caused by the virtual welding of the memory slot. Press the left side the memory slot vigorously, the MacBook Pro doesn't crash, when press the right side of the memory slot, the screen is blurry directly. Check MacBook schematic diagram and boardview.

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Macbook Repair Guide Repair Case v1 Based on the MacBook schematic diagram, we suspected it's the problem of the 6 Pin and 10 Pin of the memory slot. Use digital multimeter to measure the 6 Pin and 10 Pin, the resistance value for this two Pins will jumps when we press the memory slot vigorously, now we confirmed it's caused by the virtual welding of the memory slot. Fix the MacBook motherboard on soldering station to re-weld the memory slot.

After welding, when the MacBook Pro motherboard cools, install 2 memory, and then turn on MacBook Pro. After entering the system, no matter we press the keyboard or type on the keyboard, the MacBook Pro all works normally. Test it for few hours, the MacBook Pro works properly. The problem has been solved!

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MacBook A1532 12 inch Blurry Screen Problem A 12-inch MacBook need to be repaired, the fault described is that the MacBook screen can display properly after booting, however, after using it for a while, the MacBook stop running and the screen is blurred. The model of this MacBook is A1532, it was released in 2016, the motherboard model is 820-00244-A. This MacBook was checked by Apple Care, the result is that it's the problem of the MacBook display IC, it needs to replace the MacBook motherboard. Because this MacBook is out of warranty, it's too expensive for replacing the motherboard. Now, we're going to fix it. Connect 12-inch MacBook to the power supply via Apple lightning cable, press the MacBook power button, the screen displays properly and then enter the system. After using it for a while, the MacBook suddenly stop running, and then the MacBook screen blurs. According to our experience, this problem usually is cause by SSD IC or CPU. Because this is the MacBook display IC problem, and the display of the motherboard all are connected to the CPU, so we can confirmed that it's the CPU problem and cause MacBook stop running and blurry screen problems. Use screwdriver to remove the screws fixed the rear case, disconnect the MacBook battery, and then remove the MacBook motherboard. Put the MacBook motherboard on the WL Aluminum Alloy Pad, apply some high temperature tape to the chips next to the CPU to protect it.

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Fixing the motherboard on the BGA welding station, we usually need to set a reasonable temperature for the BGA welding station to dry the motherboard and dry the water on the internal motherboard. The main purpose is to prevent the motherboard from deforming, or the chip is damaged by high temperature.

Apply some solder paste on the CPU solder pad, and then use hot air station to solder the low temperature tin wire to the solder pad, and then use BGA desoldering wire to clean the solder pad.

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Next directly replace the old CPU with the new CPU, and then install the MacBook.

Finally, press the power button on MacBook, the MacBook is turning on smoothly. After using it for several, the MacBook is working properly, the problem has been fixed.

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MacBook Pro A1502 Screen no Display after Booting Press the power button on MacBook Pro, few seconds, we can hear the ring for booting, but the MacBook LCD screen doesn't display, the MacBook screen doesn't has any response. The model for this MacBook Pro is A1502, which was release in 2015, the MacBook motherboard model is 820-4924-A. Here is a solution for fixing this problem. Test the MacBook Pro again. Press the MacBook Pro power button, the MacBook Pro is turned on, because we can hear the booting ring, but the MacBook Pro screen keeps black, it doesn't display. Connect the MacBook Pro to the DC power supply to the current, there is a charging current. Now we need to disassemble the MacBook Pro. Use screwdriver to remove the screws that fixed the rear case to open it, and then disconnect the MacBook battery. First check the screen flex cable interface to see if here is a water damaged or oxidation phenomenon. Re-install the screen flex cable and test it, but the problem still exists, the MacBook Pro screen still doesn't respond. Next we need to remove the MacBook Pro motherboard to check whether there are some obviously faulty points. Put the MacBook motherboard under the Microscope to observe, after checking the both side of the MacBook motherboard, we didn't find the obviously damaged traces. Connect MacBook motherboard to the DC power supply, supply power the motherboard, the current is normal. Directly connect the HDMI to external display, it displayed properly. Seems the problem is on the MacBook Pro screen, remove the MacBook Pro upper part.

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After observation, the screen flex cable interface on the side of the MacBook motherboard has no problem.

Disassemble the screen shield cover, and then disassemble the antenna, we can see that the screen flex cable interface has an oxidation phenomenon.

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Directly replace the MacBook screen flex cable, and then clean up the flex cable interface with PCB cleaner. After installing the screen flex cable, connect it to the motherboard and test it.

Connect the upper part to the MacBook Pro motherboard, supply power to the MacBook, the MacBook Pro screen displays normally. Assemble the MacBook Pro, entering the system to test it, all functions tested are normal, the repair is over!

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Part-8 Troubleshoot MacBook Charge Failure

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MacBook Air won't Turn on and won't Charge Connect MacBook Air to power supply, the green light is lit, press the power button, the MacBook Air doesn't respond, it doesn't turn on, and the MacBook Air battery has no charge current, we need to solve these problem. The MacBook model is A1466, the motherboard model is 820-3437-B. Remove the rear case of the MacBook Air, disconnect the MacBook battery. Measure the MacBook Air by DC power supply, the current measured is 0.015, seems the standby voltage has the problem, because the normal standby voltage is around 0.3.

Remove the MacBook motherboard to check whether there are any traces of water damaged or other obvious damage, it's not found the obvious faulty point.

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Macbook Repair Guide Repair Case v1 Supply power to the MacBook motherboard, and then measure it with DC power supply, the current still no response, which means it's the problem of the MacBook motherboard. Check schematic diagram and boardview. Measure the standby voltage, the working condition when EC is standby, and the working condition when MacBook CPU is standby. After measurement, the voltage for the charge inductor L7130 is 8.6V, it's normal.

Measuring the standby 3.3V inductor L7560, there is no voltage, while it should be has the voltage when it's in standby status, if without this voltage, then the MacBook will not turn on. The PP3V3_S5_REG_R voltage is generated by the chip U7501 TPS51980A, check the working condition for the chip, main power supply 23 pin VIN voltage 8.6V is normal, measure the open signal 12 pin SMC_PM_G2_EN, there is no voltage, while the normal voltage is 3.3V. When the EC chip working conditions are normal, it will emit SMC_PM_G2_EN when it receives the SMC_BC_ACOK voltage.

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SMC_BC_ACO was sent by the 14 pin of the chip U7100, measured the voltage of the SMC_BC_ACOK is 3.3V, it's normal, but why EC didn't send SMC_PM_G2_EN open signal after receiving SMC_BC+ACOK signal? We need to check the working condition for the EC.

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Macbook Repair Guide Repair Case v1 Check power supply VBAT, VDDA, VDD, VDDC, all voltage measured are normal. Check reset signal SMC_RESET_L, the voltage is 0, which is abnormal, because the normal voltage is 3.3V. SMC_RESET_L signal is sent out by U5110 5 pin, measuring the 5 pin, there is no voltage. Check the main power supply 3 pin VIN of the U5110, the voltage is 3.2V, this is abnormal, and the normal voltage is 3.42V. The voltage for the resistor R5127 1 pin is 3.42V, the voltage for 2 pin is 3.2V, and the voltage is getting lower after passing through 0ohm. Use digital multimeter to measure the resistance value for the R5127, now it's about 10Kohm, we need to replace resistor. Use hot air rework station and tweezers to remove the resistor, and then install the new on. After replacement, supply power to it, now the current jumps normally.

Assemble the MacBook Air, supply power to it, now the MacBook Air can be turned on smoothly. Install the MacBook battery and charge it, now the charge current is normal, the MacBook Air charges normally. After entering the system, test the keyboard, trackpad and WIFI functions, they all works properly.

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How to fix MacBook Pro A1278 Battery Charge Failure? This MacBook Pro has battery charge failure, the MacBook battery won't charge. This MacBook Pro model is A1278, the motherboard model is 820-2936-B. After connecting the MacBook to the power supply, the power light is green, but the MacBook battery is not charging, how to fix it? According to our experience, for the battery charge failure, first we should consider whether it was caused by battery damage, so we try to fix this battery charge problem by replacing the new MacBook battery. Disassemble the MacBook Pro with screwdrivers, open the rear case, disconnect the MacBook battery and remove it, then install a new MacBook battery. After replacement, the MacBook Pro can be turned on, but the power light keeps green all the time and won't charge, which means it's not caused by the damaged battery. Disassemble the MacBook Pro again, remove the MacBook motherboard to check if it has water marks or obvious traces of damage. After checking, we don't see any obvious failure. Check MacBook schematic diagram and boardview.

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Macbook Repair Guide Repair Case v1 Find the relevant circuit of the charging circuit and find the battery interface on the boardview.

From the boardview, we can see that the battery interface is J6950, open the MacBook battery interface circuit on the schematic diagram.

Check the pins of the battery interface, 1 2 3 10 11 12 13 Pin all is grounding Pin, 4 Pin and 6 Pin are clock and address bus, 5 Pin is connect to the ground via resistor R6950, 7 8 9 are main power supply PPVBAT_G3H_CONN, the MacBook recharges and discharges through these Pins.

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Macbook Repair Guide Repair Case v1 For this MacBook failure, it can be discharged, but can't recharge, which means the discharge circuit of the motherboard is fine, so first we can measure the battery interface 2 important signal 4 Pin and 5 6 Pin system management bus.

They communicate with U4900 EC, we can use Oscilloscope to measure the waveform, first we can use digital multimeter to measure the voltage. Measure SMBUS_SMC_BSA_SCL clock, the voltage is 3.3V, which is normal. The voltage of the SMBUS_SMC_BSA_SDA address signal is 3.3V, which is normal. Voltages are normal, then we need to use oscilloscope to measure it, EC and communication of the batter are normal. Use Oscilloscope to measure SMBUS_BATT_SDA, the waveform is normal.

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Then measure SMBUS_SMC_BSA_SCL clock, there is no waveform, only 3.3V voltage, while the normal state is it has waveform and voltage. Check schematic diagram, SMBUS_SMC_BSA_SCL is connected to charge IC and EC.

Replace the charge IC ISL6259, supply power to it, but the failure is still the same. Next we need to replace the EC IC, after replacement, supply power to it, the charge current is normal, use oscilloscope to measure the waveform of the SMB_US_SMC_BSA_SCL signal, now the waveform is normal.

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Assemble the MacBook Pro and test it, now it turns on properly, and the charge function and discharge function are normal!

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MacBook Air A1466 doesn't Charge after Water Damaged Here is a MacBook with charge problem, it can't recharge because it's damaged by water. After pressing the power button on MacBook, charging icon is displayed on the MacBook screen. Connect the power supply, the MacBook doesn't respond, the power light is not lit, the MacBook doesn't charge.

This MacBook model is A1466, the motherboard model is 820-00165-A. Use screwdrivers to remove the MacBook Air rear case, disconnect the power supply, it's clearly see that there are traces of water. Check the power supply board and connect cable, it's obviously damaged by water.

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Macbook Repair Guide Repair Case v1 Remove the MacBook motherboard, check the reverse side of the motherboard side of the motherboard, there is no obvious sign of water, the inlet area is concentrated on the front of the motherboard. Firstly, use PCB cleaner to clean the area where is oxidized by water. Check MacBook schematic diagram and boardview.

We can see that Q7155 is the charge and discharge MOS tube, damaged MOS tube will cause MacBook won't charge and can't discharge. Check MacBook battery connector, it's severely oxidized, we need to replace the Q7155 and MacBook battery connector.

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Directly remove the Q7155 and battery connector, and then install the new Q7155 and battery connector to the MacBook. Now checks MacBook screen flex cable connector, it's obviously damaged, we need to replace it. After replacement, connect the new power board and cable to the battery to test it, the problem still the same, it displays charge icon, after a while, the MacBook screen turns black. Remove the MacBook battery, it's also oxidized by water. Replace it with the new battery, connect to the DC power supply, there is charge current, and the MacBook screen displays normally. Because the HDD is not installed, so after a while, the screen shows a question mark.

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Macbook Repair Guide Repair Case v1 Restart the MacBook Air, hold the option button, it displays for a while, and then still shows a question mark, which means the keyboard doesn't work. Disconnect the power supply to check MacBook keyboard and trackpad. After observation, we found the keyboard, trackpad and connection flex cable all are moldy and oxidized. Replacing the new MacBook keyboard, trackpad and connection flex cable, and then supply power to it to test, after powering, click the option button, now it displays the interface for selecting the system.

Install the HDD, WIFI card, the MacBook Air enters system smoothly. Testing the keyboard and exterior accessories, they all work normally. Check MacBook battery, the battery can be charged or discharged properly. The MacBook Air charge problem has been solved!

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Liquid-damaged MacBook A1534 not Charging A liquid damaged MacBook doesn't charge, the MacBook model is A1534, which was released in 2015, the motherboard model is 820-00045-A, we need to solve this charge problem to get the MacBook back to normal work. The fault described was that some liquids accidentally entered the MacBook, after drying the MacBook, connect MacBook to the power supply via Apple lightning cable, it's found that the MacBook is not charging. Firstly, we need to test this MacBook. Press the MacBook power button, it displayed the charge icon, connect the MacBook to the power supply via Apple lightning cable, sometimes it can be charged, but sometimes not, it jumps repeatedly. And we still can see the liquid on the keyboard.

We need to disassemble the MacBook to check interior of it. Use screwdrivers to remove the screws of the rear case, open the rear case, we much be careful to the connection flex cable of the touch control board.

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Macbook Repair Guide Repair Case v1 We can't open the rear case completely, after opening it, disconnect the flex cable that connected to the MacBook motherboard and the remove the screws that fixed the MacBook battery. After opening it, we can see visible traces of liquid inside the MacBook.

It's mainly entered from the power supply interface, there is a lot of liquid on the MacBook battery and keyboard. First replace the new power supply flex cable to try.

After replacing the new power supply flex cable, supply power to it, the screen is on, and we can see that the backlight of the MacBook screen also has a lot of liquid.

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Disconnect the power supply, clean the area that entered the liquid with alcohol, we use Titanium Alloy Tweezers to clamp cotton with alcohol to clean it.

Now we need to replace the power supply flex cable, we need to separate the upper part of the MacBook completely. Remove the old power supply flex cable, we can see that it's totally corroded.

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After replacing the power supply flex cable, install the MacBook, connect the MacBook to the power supply via Apple lightning cable to supply power, it worked, the MacBook entered the system properly, and the charge function works normally. Test the keyboard, it also works good. The problem has been solved!

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MacBook Pro Battery won't Charge with PCB Repairing A MacBook Pro battery won't charge, when the charger is inserted, the MacBook has no response, we need to fix this MacBook battery no charging problem. The model for the MacBook Pro is A1502, the motherboard model is 820-3476-A. Because it's the battery charge problem, so firstly we try to fix it by replacing the MacBook battery, if it doesn't work, then we will check MacBook motherboard and repair it. The repair process is as follows. Use screwdriver to remove the screws that fixed the rear case, and then open the rear case. Disconnect the MacBook battery, and then remove the MacBook battery. Install the new MacBook Pro battery, and then test it, but the charge problem is still exist. Now we need to check MacBook motherboard. Disassemble the MacBook again, remove the MacBook motherboard and observe it, there are no traces of water or oxidation. Check schematic diagram and boardview, find the MacBook battery interface, J7050 is the battery interface.

Based on schematic diagram, we know that PPVBAT_G3H_CONN is the battery charge pin, we can check it from this signal.

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Macbook Repair Guide Repair Case v1 PPVBAT_G3H_CONN came to MOS tube Q71155 5 pin on P-Channel.

It was control by charge IC U7100, and it supply power to motherboard system via inductor L7130. As we know, the MacBook uses a hybrid circuit, and the battery charge voltage is the same as the adapter supply voltage. So, we need to check the working condition of the charge IC to see if it's normal.

The MacBook Pro can be turned on by power supply, which means the power detection part is normal, and U1700 power working part has no problem. We need to check MacBook battery detection part, the 6 pin CELL of the U7100 is battery core setting, high level set to 3 knots. It's provided by the PP3V42_G3 through the resistor R7112 to pull up,set the battery voltage in 12.6V. After measurement, the U7100 is high level, which is normal.

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Next check U7100 17 pin and 18 pin, these 2 pins are the current detection pin for the battery. Use digital multimeter to measure the 18 pin CHGR_CSO_P, the value tested is 12.6V, and the 17 pin CHGR_CSO_N is 11.9V, and then jumps to 12.2V, which is abnormal, the normal value should be same as to the value of the pin 18. 17 pin is connected to inductor R7150 13 pin via inductor R7152, measure resistance of the inductor R7152, the data tested is normal, and the connection between R7150 and R7152 2 pin is normal. Now we can replace the charge IC and test it, after replacement, connect the battery, but the failure still exist, no charging and no leaking, seems this problem is not caused by charge IC. Check the circuit which connected to 17 pin, it connects to the back level via R7152 to R7150, and then connect to several capacitors.

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Is it caused by a leakage of capacitor? The battery detection voltage is unstable. Find then capacitor C7155 on the schematic diagram.

Find its real position on the MacBook motherboard, we found the capacitor is moldy, seems the problem is here. Use hot air rework station to replace the capacitor directly, and then measure the 17 pin again, the voltage tested is 12.6V, it's normal. Assemble the MacBook Pro, the power green light has turned orange, which means the MacBook battery has been detected. The current is 0.113, which means the MacBook battery can be charged. After five minuses, the charge current turns normal value. Disconnect the power supply, the MacBook battery leaks normally, the MacBook charge function is back to normal.

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Part-9 Troubleshoot Other Problems

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MacBook Pro Shuts Down when enter the System This MacBook has a boot failure, the MacBook Pro can be displayed after booting, while it shuts down suddenly when entering the system. This MacBook Pro model is A1278, the motherboard model is 820-3115-B. After pressing the power button, the MacBook screen displays normally, and then system process bar appears, while the progress bar was not halfway through, the MacBook turned off automatically, the MacBook Pro can't enter the system successfully, we need to solve this problem.

Measure the MacBook Pro with a DC power supply, and when the process bar runs less than half, the MacBook suddenly shuts down, at this point the current is 0.328, which should be the current of the battery charge.

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Macbook Repair Guide Repair Case v1 Open the MacBook rear case, disconnect the MacBook battery, and then connect it with a power supply.

The result is the same, the process bar runs less than half, and then the MacBook shut down, the current directly drops to standby current. Restart the MacBook Pro, it still can be displayed after booting, which means this is not the protective power drop, because if it's a protective power drop, then the MacBook will not power on again after pressing the power button. Based on the above analysis, we can first troubleshoot external configuration issues, first disconnect the camera connector, optical drive connector and WIFI antenna, and then power on MacBook Pro to test it, the problem is still the same. Disconnect the keyboard, and turn on MacBook Pro again, the MacBook Pro enters the system properly. The power button was connected with the keyboard, so we suspected that the MacBook power button has some problem, and it causes current drops.

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First replace the new keyboard, after installing the new keyboard, the MacBook Pro can enter the system normally after booting, and those buttons are working properly, which means the original keyboard is damaged. Remove the MacBook motherboard, optical drive connector, and then we start to replace the keyboard.

First remove the backlight strikers, this keyboard was fixed by screws, so we need to remove those screws, directly remove the keyboard, and then install the new keyboard.

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After replacement, turn on the MacBook, the MacBook Pro enters system successfully and then tests the keyboard, the new keyboard works perfectly, and the charge function also is normal. The MacBook Pro problem has been solved!

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MacBook Pro Runs Slowly when Using Battery A MacBook Pro runs slowly when using the battery, and the mouse also is stuck as it moves, while it runs normally when it's connected to the power supply. This MacBook Pro model is A1278, the motherboard model is 820-2936-B. This MacBook Pro went into some water before, but it’s still can be used, after using it for a while, it's found that the MacBook Pro runs slowly when used the battery alone. How to fix it? Here is a solution. First of all, test the MacBook Pro. Turn on MacBook Pro with battery only, it reacts slowly, and the mouse also will stuck when moving. Connect an external USB mouse, the problem is still the same, but when connects it to the power supply, the mouse moves normally, and the MacBook Pro also runs in normal speed. Based on the trouble phenomenon, we analyze some reasons that causing this problem: - MacBook Pro battery itself problem - MacBook Pro motherboard power detection problem - MacBook Pro external configuration problem Disassemble the MacBook Pro rear case by screwdrivers, and then replace the MacBook Pro battery directly. After replacement, turn on MacBook Pro, but it still runs slowly. Then disconnect the MacBook Pro keyboard and WIFI flex cable, turn on MacBook to test, the problem is still the same. Now, we confirmed it's caused by the MacBook Pro motherboard problem. Take out the MacBook Pro motherboard, first observe whether the motherboard has visible traces of water under the Microscope. As we can see, the chips on opposite side of the motherboard are obviously blackened. Open the MacBook Pro schematic diagram and boardview. Click here for download schematic diagram and boardview.

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Find the components that on the water traces area on the boardview.

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Macbook Repair Guide Repair Case v1 From the boardview, we can see that Q5300 is a composite Mosfet tube, which is mainly used to detect the PBUS voltage, it passes through the 3 PIN output voltage, and then through resistor R5303 R5304 to separate the voltage to generate the approximately 2V voltage SMC_PBUS_VSENSE , and then send to EC as the detection. Check the MacBook Pro motherboard, we see that 2 resistors near Q5300 are obviously blackened, they were R5301 and R5302.

Use hot air rework station to replace 2 pieces 100K resistors, power it to measure the 3 Pin voltage of the Q5300, it's 0V. Check the working condition for this Mosfet, 2 Pin received the PM_SLP_S3_R_L high level voltage, pass 6 Pin and 1 Pin, 6 Pin pass though R5302 to 5 Pin of the Mosfet, 4 Pin is the main power supply of the PPBUS_G3H, when the 5 Pin is low level voltage, it will pass 3 Pin and 4 Pin, PPBUS_G3H will separate the voltage via resistor R5303 and R5304. Use digital multimeter to measure the 2 Pin of the Q5300, it has 3.3V, the voltage for 4 Pin is 12.5V, and the voltage for 5 Pin is about 12.3V, normally, the 5 Pin should be low level voltage.

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Disconnect the power, use digital multimeter to measure the R5301 and R5302, we found the 2 Pin of the R5302 and the 2 Pin of the R5301 are abnormal, their connection point are blackened. Use BGA graver blade to scrape it, we can clearly see that it's disconnected. Use hot air rework station to solder a jump wire to connect them, and then measure it again. Now the voltage of the Q5300 3 Pin is about 12V, and then voltage of the R5303 2 Pin is about 2V, which are normal. Install the MacBook Pro, turn on MacBook Pro with battery only, now it enters system faster, and the mouse also isn't stuck, all other functions tested are normal. This MacBook Pro has been fixed.

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MacBook Pro no Sound with Motherboard Repairing When playing music on MacBook Pro, there is no sound, both the speaker and earpiece are no sound, after checking, we know it's caused by MacBook motherboard, so we need to fix MacBook pro no sound problem by repairing motherboard. The model for this MacBook Pro is A1502, the motherboard model is 820-3476-A. The repair process is as follows. Firstly, test the MacBook Pro. Power on MacBook Pro, the MacBook screen displays normally after pressing the power button, but we didn't hear the boot music. The fault described is that the MacBook playing the music, after inserting the earpiece, the sound was gone, the MacBook just keep silence. Next, try to fix it by re-installing the system. However, after installing the system, the MacBook still no sound. Entering the system, by pressing the keyboard to add and subtract sound, it shows a prohibited icon, the music icon also is black. Now, we can confirm it's the problem of the MacBook motherboard hardware. Remove the screws that fixing the rear case of the MacBook by screwdriver, and then open the rear case. Remove the MacBook Pro motherboard directly.

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Macbook Repair Guide Repair Case v1 Observing the MacBook Pro motherboard carefully to check whether there is water traces or obviously faulty point, there are no obviously traces of water and damaged components. Check MacBook schematic diagram and boardview, finding the voice control circuit, we can see that it's U6201.

Now we need to find out voice chip U6201

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Macbook Repair Guide Repair Case v1 Connect MacBook Pro motherboard to the DC power supply, and the supply power to it to test the boot current. After measurement, we know that the current is higher than normal value when booting. When we start to measure the working condition for the chip, we found the U6201 IC is overheated. Disconnect the DC power supply, use hot air rework station to heat U6201, and then use tweezers to remove it, finally install the new U6201 IC. After replacement, use DC power supply to measure it again, now the current tested is normal. Install the MacBook Pro, press the power button, now we can hear the boot music, after few seconds, the MacBook Pro is turned on smoothly. Now test the sound function, playing the music, we can hear the sound. The MacBook has been repaired!

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MacBook A1534 12 inch Keyboard Replacement A water-damaged 12-inch MacBook keyboard is unavailable, we need to replace the keyboard. The MacBook model is A1534, which is released in 2015. The fault described is that some water into the MacBook, after drying the water, pressed the MacBook power button, and fortunately, the MacBook turned on normally. Unfortunately, the MacBook keyboard doesn't work, it has no response when we touch it. Before we replace it, we need to test the MacBook. Connect MacBook to the power supply via Apple lightning cable, and then press the MacBook power button, after few seconds, the MacBook screen displays properly, and then the 12-inch MacBook turned on successfully. Tap the MacBook keyboard, several keyboard buttons are not working, we judged that it's the MacBook keyboard problem.

Power down the MacBook, disconnect the power supply. Use screwdrivers to remove the screws fixed the MacBook rear case, and then remove the rear case. In this step, we need to take good care of the keyboard touch control board flex cable, don't pull this flex cable off.

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Disconnect the MacBook battery, and then separate the D shell and C shell on the lower part.

The MacBook keyboard was connected to the C shell, the upper layer on the keyboard is the backlight stickers of the keyboard, and we need to remove it first. We can carefully remove the stickers by the hand, because it's glued by glue.

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After removing the backlight stickers, we can see the screws that fixed the keyboard.

Using the special screwdrivers to remove the screws that fixed the keyboard, after removing the screws, we can't take off the keyboard directly, because there is a double-sided adhesive between the keyboard and C shell. The MacBook keyboard uses a butterfly structure, it is wider than the scissor structure, and it uses a monomer structure made of harder materials, it's easy to damage the keyboard if we trying to remove it directly. Before we remove the keyboard, we can use hot air rework station to heat the keyboard at the reasonable

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Macbook Repair Guide Repair Case v1 temperature, heating it for a while, so we can easy to remove it, but still have to disassemble it carefully.

After removing the keyboard, we can install the new keyboard. When we install a new keyboard, we don't need to sticky double-sided adhesive on the keyboard, we just need to install the screws that were disassembled before.

Finally, assemble the MacBook, power on it and test it, now the keyboard is working properly, the keyboard replacement is over!

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How to Replace MacBook Pro A1398 Broken LCD Screen? The MacBook Pro LCD screen is damaged and we need to replace it. This MacBook Pro model is A1398 and was released in 2015. As we know, screen replacement is a common situation, all we need to do is remove the damaged LCD screen and install the new one. In this process, we need to be careful to avoid a second damage to the device. How to replace this A1398 MacBook Pro broken LCD screen? Before we are going to remove the broken MacBook Pro LCD screen, we need to test the MacBook first. Press the MacBook Pro power button, the MacBook Pro screen displays smoothly, just the LCD screen is broken. The broken screen will affect the usage of the MacBook, so we have to replace it.

Shutdown the MacBook Pro, use the screwdrivers to remove the screws that fix the MacBook rear case, and then remove the MacBook rear case. Disconnect the MacBook Pro battery, and then remove the upper part of the MacBook.

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After removing the rubber ring, we need to use professional screen disassembling tools to remove the MacBook LCD screen. Use hot air rework station to heat the MacBook LCD screen, carefully control the temperature, don't be too hot. At the same time, use professional screen gravel thin blade to remove the LCD screen slowly.

After removing the MacBook LCD screen, we need to clean the double-sided adhesive, so that it doesn't cause poor connectivity between the screens. And please don't damage the backlight part.

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Next we need to disassemble the iron strip under the LCD screen, because the new LCD screen doesn't comes with it. After disassembling the iron strip, fix it by doublesided adhesive. Now we need to install a new MacBook LCD screen, the rubber ring, screen frame cover, and then use screws to fix them. After installing the upper part of the MacBook Pro, press the power button to turn on the MacBook Pro, the MacBook LCD screen displays properly. When it accesses the system, test other function, all works well. The MacBook LCD screen replacement ends!

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MacBook Pro A1425 Keyboard Replacement There are several buttons on the MacBook Pro keyboard that don't work, after testing, we confirmed it's the problem of the MacBook Pro keyboard, we need to replace it. Here is the guide for replacing MacBook Pro keyboard. The model for MacBook Pro is A1425, the motherboard model is 820-3462-A. Press the MacBook power button to turn it on, it's turned on smoothly, and then test the MacBook Pro keyboard. Randomly type the buttons on the keyboard, most of them are working properly, but the 3 buttons of V F J don't respond to touch unless we press it vigorously. According to our repair experience, we confirmed it's the keyboard problem, and we can fix it by replacing the new keyboard. In order to replace the MacBook keyboard, we need to disassemble the MacBook, remove the MacBook motherboard, speaker and battery. Use screwdrivers to remove the screws that fix the rear case, and then remove the MacBook rear case. Next remove the MacBook battery and speaker, finally remove the MacBook motherboard.

Below the MacBook motherboard is the backlight of the keyboard, carefully remove the backlight, we can see that the MacBook keyboard and the C shell are nailed through the code nail, we can unplug the MacBook keyboard directly with pliers.

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After removing the MacBook keyboard, we can install the new keyboard and fix it with screws. For those code nails on the shell, some of them can be removed when we unplug the keyboard, but some of them can't be removed, then we need to use pliers to remove them.

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Macbook Repair Guide Repair Case v1 After assembling the new keyboard, install the screws to fix the keyboard.

When the keyboard replacement is finished, install the MacBook backlight, motherboard, speaker and battery. Press the MacBook power button, after entering the system, test the MacBook keyboard, now it works well. Continue to test other function, they all works well. The MacBook Pro keyboard replacement is done.

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How to Replace MacBook Pro A1706 Keyboard? A MacBook Pro keyboard failed to work, it's no responded to our touch and control, we need to replace the new keyboard for this MacBook Pro. Before us going to replace it, we need to know the details for this MacBook Pro, after checking, the model of this MacBook Pro is A1706, it was released in 2016. Connect MacBook Pro to the power supply via Apple lightning cable, and then press the MacBook Pro power button, after few seconds, the MacBook Pro enters system properly. Now we need to test the keyboard, touch the keyboard as usual, there are a few buttons that don't respond, we try to click it with more force, but it still no response. Test other functions, all works well, now we confirmed that it's the MacBook Pro keyboard problem, we need to replace it with the new keyboard. Power down the MacBook Pro, and then disconnect the power supply. Use screwdrivers to remove the screws that fixed the rear case of the MacBook Pro, and then remove the rear case.

After removing the rear case, we can see that there is a sticker on the keyboard, the backlight of the keyboard is together with the keyboard. First we need to disassemble the fixing screws on the keyboard, next we need to use pliers to remove the code nail one by one on the keyboard. In this step, we need to know that we can't pull this keyboard with great force, because it's easy to crack. After removing the code nail, we can take off the MacBook Pro keyboard.

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After handling the code nail, we can start installing the new keyboard to the MacBook Pro.

First fix the keyboard on the MacBook Pro, next use screwdriver to install the screws, and then stick the keyboard sticker, finally assemble the MacBook Pro motherboard. Connect MacBook Pro to the power supply via Apple lightning cable, and then press the MacBook Pro power button, the MacBook Pro enters system successfully, now we can test the keyboard. Click the each buttons on the keyboard, they response properly, after using it for a while, everything works perfectly.

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MacBook Pro A1707 15 inch Display Screen Replacement The MacBook Pro display screen is broken, causing the MacBook Pro screen has the backlight but without images, we need to fix it by replacing the MacBook Pro display screen. After observation, the model for this MacBook Pro is A1707, which was released in 2016. The MacBook Pro uses a 15-inch retina display screen, which with high brightness LED backlight, so it has high contrast. Here a guide to replace the MacBook Pro 15-inch display screen. First, test MacBook Pro. Press the MacBook Pro power button to turn it on, we can see that the upper-left corner of the MacBook Pro screen is cracked, the MacBook Pro screen backlight displays normally, but there is no image on the display screen. External connection an HDMI, it's displayed correctly. Therefore, we confirmed that it's the problem of the MacBook Pro display screen.

Second, disassemble the MacBook Pro. Use DIY Opening tool kit to disassemble the MacBook Pro, carefully remove the MacBook Pro rear case, and then take out the MacBook Pro display screen part.

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Now we need to remove the LOGO screen strips, actually, these strips are glass strips. Before we remove it, we need to use QUICK 861DW hot air rework station to heat it, and then use graver blade to remove it carefully.

After remove the strips, next it's to remove the rubber rings, and next is remove the LCD screen.

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Heat the LCD screen by hot air rework station, and use a thin BGA remove blade to disassemble the LCD screen slowly. In this step, please note that the temperature of the QUICK 861DW hot air rework station can't be too higher, otherwise, it will damage the backlight that inside the LCD screen.

After removing the LCD screen, we need to clear up the double-sided adhesive, so that it doesn't cause screen bad contact condition.

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After handling the double-sided adhesive, we need to clear up the dust on the backlight, and then install the new MacBook Pro display screen. In this step, we must pay attention to the installation of the iron belt above the LCD screen, which much be affixed with double-sided adhesive, and it should be flat with the LCD when installing. The role of this iron strip: - Press the LED light, so the LED light won't leak out - Protect the MacBook LCD screen, fix the LCD screen.

After the LCD screen is installed, assemble the MacBook upper part back to the MacBook Pro. After assembling, test the MacBook Pro display screen, now it works normally, the image is displayed smoothly.

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MacBook A1534 PIN Code/Firmware Lock How to unlock PIN lock and firmware lock on MacBook? Here is a MacBook, which has PIN lock and firmware lock. As we know, if the MacBook is locked by PIN code or firmware, and you forgot the password, and then we can't use the MacBook as usual, so we have to unlock it. The MacBook model is 1534, which was released in 2015, the motherboard model is 820-00045-A, and here is guide to unlock PIN lock and firmware lock on A1534 MacBook. After entering the system on MacBook, it displayed PIN lock, press the Option button, the firmware lock appears. Now, we need to use unlock tool to unlock it. The unlock process is as follows. After powering the MacBook, the PIN code appears, this password has 4 digit and 6 digits. Restart the MacBook, press and hold the Option button, the firmware lock appears.

Only by solving this lock can the MacBook be operated, otherwise the MacBook is unresponsive. Power down the MacBook, and use screwdrivers to remove the screws that fixed the rear case to remove the rear case, and then disconnect the MacBook battery.

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Macbook Repair Guide Repair Case v1 Find out the position of the BIOS chip on the MacBook motherboard, this MacBook BIOS chip is a glass tube chip, which is easy to damage if we remove it by QUICK 861DW hot air rework station.

Check the boardview to find out the power supply pin of the BIOS chip, and then find the connection point that connected to the BIOS chip power supply pin.

These pins all are connected to the power supply pin of the BIOS chip, we can find a point that easy to connect.

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Choose this connection point (check the following picture), because it's easy to solder the wire.

Connect it with power supply cable, generally set the power supply voltage around the 2.5V to 3V. Find the SAM socket on the MacBook motherboard, and then confirm the pin 1 of the SAM socket on the boardview.

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Connect the unlock tool, use DC power supply to add a 2.5 to 3.0V power supply on the BIOS chip. To unlocking entire MacBook, usually we don't need to disassemble the motherboard, we can just disconnect the motherboard battery.

After connecting the programmer, open the software on the computer, read the BIOS data. Save the BIOS data that read, and open the special unlock software.

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Remove the password from the password area of the BIOS data, and then re-save it. After unlocking the password, re-write the BIOS data that without password to the chip.

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Macbook Repair Guide Repair Case v1 When finished it, remove the unlock tool. Supply power to it and turn it on, press the Option, Command, R and P button at the same time to clear the BIOS, when the MacBook automatically restart, we can release those buttons. Now, the MacBook can enter the system normally, the MacBook has been unlocked!

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How to Unlock PIN Code/Firmware MacBook Pro A1707 A 15-inch MacBook Pro has PIN code lock and Firmware lock, it can't be used normally, we need to unlock PIN code lock and Firmware lock on this 15-Inch MacBook Pro. After checking, we know that the model for this MacBook is A1707, it was released in 2016, and the board model is 820-00281-A. First of all, we need to enter the system to test the MacBook. Press the MacBook power button, the MacBook screen displays normally, after entering the system, there is a PIN lock. Press the "Option" button, there is a firmware lock. How to unlock them?

Power down the 15-Inch MacBook Pro, and disassemble the MacBook, take out the MacBook rear case, disconnect the MacBook battery. Now we need to check MacBook boardview. Check MacBook schematic diagram, carefully to find the power supply connection pin of BIOS chip, and the pin that was connected by the front of the motherboard and the BIOS IC power supply 8 pin.

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According to the MacBook schematic diagram, we can connect the power supply cable to pin 1 of the capacitor C6101. Put MacBook under the Stereo Zoom Microscope, connect the power supply cable, and add an external voltage 2.5V-3V.

Next, find the SAM socket on the MacBook motherboard, and find the first pin of the socket. Connect the unlock tool to the pins of the corresponding socket, and then open the programmer software on the computer. Click intelligent recognition button (SmartlD), so it will automatically recognize the BIOS IC model, and then click Read button, so it will automatically read the information of BIOS IC. After the data is read successfully, save it.

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Now we need to use special unlocker software to change the information of the password area, after the change, save the BIOS information.

Click "Write" button, write the BIOS information after removing the password to the BIOS chip. After successful writing, remove the unlock tool, install the MacBook battery. Please press the Option, Command, R and P button at the same time while power on MacBook, so it can clear BIOS. After the MacBook auto reboot, please release the buttons. Now the MacBook is entering the system smoothly, and there is no PIN lock or firmware lock when you press the Option button. The MacBook Pro has been unlocked successfully.

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I wish you all the best and look forward to hearing your success story.

To your success.

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