Hello, I bought this Mac from a friend, he said that it simply stop working. The MacBook looks very clean but does not power on, stuck on 5v 0.42A, and sometimes display 5V and 0A (then 0.071A and again 0A).
I opened it looking for some problem, it was not touched before for sure and the board is very clena, no spot of corrosion at all from what I can see. Voltage on multimeter of the board off the case it's the same, 5V 0.42A. But then I noticed this "clicking sound" come from the board ( I attached here the audio file).
Looking on google I found this:
"Differential Diagnosis for a clicking sound from system board with low voltage as measured by a USB-C amp meter.
• Corroded or failed PP3v8_AON creation MOSFET. (Q5800, Q5820, Q5840.)
• Corroded or failed PP3v8_AON buck converter IC. (U5700)
➤ Diagnostic Steps
1. Measure voltage on PP3v8_AON. (Normal voltage = 3.8v. ) You will likely find that the voltage is low and pulsing slightly or completely absent. This confirms the diagnosis.
2. Perform a visual inspection of the system board. This failure is very uncommon without liquid damage. Often times, you will find that one of the 3v8_AON MOSFETs will be corroded, or that U5700 itself will be corroded. If the MOSFETs (Q5800, Q5820 or Q5840) are corroded, proceed to the Repair Steps below for "PP3v8_AON creation MOSFETs corroded" below. If the PP3v8_AON buck converter IC (U5700) is corroded, proceed to the "PP3v8_AON buck converter IC corroded" repair steps below.
➤ Repair Steps
PP3v8_AON creation MOSFETs corroded
- Replace Q5800, Q5820 and Q5840 together. It's important to replace all 3 MOSFETs at the same time as if one MOSFET failed, it may have damaged the others. Replacement of U5700 is not necessary as long as it isn't corroded and as long as the clicking sound does not persist after replacement of the MOSFETs.
PP3v8_AON buck converter IC corroded
- Replace U5700. Replacement of the PP3v8_AON creation MOSFETs is not required unless they are corroded or if the clicking sound persists after replacement of U5700.
Verify correct voltage on PP3v8_AON after the relevant repair is performed."
reference: repair.wiki/w/A2338_2020_13%22_MacBook_Pro
I found no visible problem on Q5800, Q5820, Q5840 mosfets, neither U5700 IC.
Then I measured voltage of P3V8_AON_VSW1 on L5800, and I got 0V.
PPBUS_VMAIN_VIN_ISNS measured on C5800 pin 1 is 7.9V
C5701
1 P3V8AON_PVCC measure 4.33V
2 GND
C5702
1 PP5V_AON measure 4.54V
2 GND
I will be really thankfull to anyone who would help me to sort out this problem and get back to life this Mac. I know I'm a real noob diagnosing problems, please be patient. Any advice is really welcome.
I opened it looking for some problem, it was not touched before for sure and the board is very clena, no spot of corrosion at all from what I can see. Voltage on multimeter of the board off the case it's the same, 5V 0.42A. But then I noticed this "clicking sound" come from the board ( I attached here the audio file).
Looking on google I found this:
"Differential Diagnosis for a clicking sound from system board with low voltage as measured by a USB-C amp meter.
• Corroded or failed PP3v8_AON creation MOSFET. (Q5800, Q5820, Q5840.)
• Corroded or failed PP3v8_AON buck converter IC. (U5700)
➤ Diagnostic Steps
1. Measure voltage on PP3v8_AON. (Normal voltage = 3.8v. ) You will likely find that the voltage is low and pulsing slightly or completely absent. This confirms the diagnosis.
2. Perform a visual inspection of the system board. This failure is very uncommon without liquid damage. Often times, you will find that one of the 3v8_AON MOSFETs will be corroded, or that U5700 itself will be corroded. If the MOSFETs (Q5800, Q5820 or Q5840) are corroded, proceed to the Repair Steps below for "PP3v8_AON creation MOSFETs corroded" below. If the PP3v8_AON buck converter IC (U5700) is corroded, proceed to the "PP3v8_AON buck converter IC corroded" repair steps below.
➤ Repair Steps
PP3v8_AON creation MOSFETs corroded
- Replace Q5800, Q5820 and Q5840 together. It's important to replace all 3 MOSFETs at the same time as if one MOSFET failed, it may have damaged the others. Replacement of U5700 is not necessary as long as it isn't corroded and as long as the clicking sound does not persist after replacement of the MOSFETs.
PP3v8_AON buck converter IC corroded
- Replace U5700. Replacement of the PP3v8_AON creation MOSFETs is not required unless they are corroded or if the clicking sound persists after replacement of U5700.
Verify correct voltage on PP3v8_AON after the relevant repair is performed."
reference: repair.wiki/w/A2338_2020_13%22_MacBook_Pro
I found no visible problem on Q5800, Q5820, Q5840 mosfets, neither U5700 IC.
Then I measured voltage of P3V8_AON_VSW1 on L5800, and I got 0V.
PPBUS_VMAIN_VIN_ISNS measured on C5800 pin 1 is 7.9V
C5701
1 P3V8AON_PVCC measure 4.33V
2 GND
C5702
1 PP5V_AON measure 4.54V
2 GND
I will be really thankfull to anyone who would help me to sort out this problem and get back to life this Mac. I know I'm a real noob diagnosing problems, please be patient. Any advice is really welcome.
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