iPhone 8 Automatic Restarted Repair

Malfunction Phenomenon

The phone is automatically restarted occasionally.

Even if we replace the new battery, the issue still remains.

Troubleshooting

The iPhone 8 Automatic Restarted issue might be related to a system issue, battery issue, or the fault of hardware.

Firstly, we connect it with the computer and restore it via iTunes, but the issue still remains. Then we connected with the charging cable to charging, but the phone still can’t be charged, and the charging symbol vanishes.

So we can confirm that the fault is related to the relevant charging circuit.

Then we can take out the phone and check the battery connector J3200, the measured diode value of pin 3 is 0, which is abnormal. Judging by this, the signal in pin 3 of J3200 is disconnected on the circuit. Then run a cosmetic inspection of the motherboard and we found the bonding pad of Q3201 has been knocked off.

So we can conclude that the fault is related to Q3201. Then remove the MOSFET and short the connection between pin2 and pin 3.

After that, measure the diode value on pin 3 of J3200, the measured value is 397, which is normal.

Then assemble it and test again, all function is normal, problem resolved.

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