Hi everyone - first time poster on here looking to embark on my first repair! Thank you in advance for any help!
My Macbook only turns on when the charger is plugged in and only the trackpad and fans show signs of life. The display, caps lock light and touchbar do not turn on. There was previous liquid damage to the touchbar but after cleaning and drying the laptop was operational for a year without any issues. There doesn't seem to be any sign of liquid damage to the board, at present.
What I have done so far:
- All of the routine diagnostic methods including SMC, PRAM/NVRAM and attempting to put it into DFU mode (Have not succeeded in making it enter DFU mode)
- I have removed the logic board completely and cleaned it thoroughly with 99% IPA
- Used multiple different chargers, including the original and other working chargers rated appropriately
I have obtained the schematic and boardview for a similar model (A2289: 820-01987) as this model's (A2289: 661-14770) doesn't seem to be available - these are attached for reference.
I have taken the following readings thus far, with the battery disconnected, charger plugged in and the laptop turned on. The schematic didn't seem to have the 'Power Aliases' page that I'm used to, so I began by taking readings of what I thought were the main power rails. Subsequently, I focused on what what I thought were relevant power rails/components for me to test - based on my admittedly novice knowledge. I surmised that the voltage on PPVCC_S0_CPU was quite low at 0.8V and therefore focused on the related rails to try and determine what may be at fault.
At this point I'm stumped and can't figure out where to go next from here! I'll be working on this all weekend and will be immediately available for any follow-ups! Thank you!
My Macbook only turns on when the charger is plugged in and only the trackpad and fans show signs of life. The display, caps lock light and touchbar do not turn on. There was previous liquid damage to the touchbar but after cleaning and drying the laptop was operational for a year without any issues. There doesn't seem to be any sign of liquid damage to the board, at present.
What I have done so far:
- All of the routine diagnostic methods including SMC, PRAM/NVRAM and attempting to put it into DFU mode (Have not succeeded in making it enter DFU mode)
- I have removed the logic board completely and cleaned it thoroughly with 99% IPA
- Used multiple different chargers, including the original and other working chargers rated appropriately
I have obtained the schematic and boardview for a similar model (A2289: 820-01987) as this model's (A2289: 661-14770) doesn't seem to be available - these are attached for reference.
I have taken the following readings thus far, with the battery disconnected, charger plugged in and the laptop turned on. The schematic didn't seem to have the 'Power Aliases' page that I'm used to, so I began by taking readings of what I thought were the main power rails. Subsequently, I focused on what what I thought were relevant power rails/components for me to test - based on my admittedly novice knowledge. I surmised that the voltage on PPVCC_S0_CPU was quite low at 0.8V and therefore focused on the related rails to try and determine what may be at fault.
At this point I'm stumped and can't figure out where to go next from here! I'll be working on this all weekend and will be immediately available for any follow-ups! Thank you!
| Component/Net | Voltage Reading |
| PPBUS_G3H | 12.49V |
| P3V3_G3H | 3.28V |
| PP3V3_S5 | 3.27V |
| PP5V_G3S_TPAD | 5V |
| PP1V8_S5 | 1.78V |
| PPVIN_S0_CPUVR_VIN | 12.49V |
| PP5V_S0_BKLT_A | 5.07V |
| PP5V_S0_BKLT_D | 5.06V |
| PP3V3_G3S | 3.27V |
| PP3V3_G3S_KBD | 3.27V |
| PP5V_G3S_CPUREG_MISC | 5.07V |
| PPBUS_HS_CPU | 12.49V |
| PP5V_MAIN_VCORE1 | 5.07V |
| CPUCORE_FCCM | 5.02V |
| CPUCORE_PWM1 | 0.4V |
| XDP_PM_RSMRST_L | 3.27V |
| CPUCORE_SW1 | 0.33V |
| PPVCC_CPU_PH1 | 0.8V |
| PPVCC_S0_CPU | 0.8V |
| PPVCCSA_S0_CPU | 1.0V |
Attached Files
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