How to Fix the iPhone 6 Plus Reboot Failure

How to Fix the iPhone 6 Plus Reboot Failure Received an iPhone 6 Plus device, it was repaired once by others before, the iPhone 6 Plus touch IC was replaced, however, after a week, it did not reboot. How to solve this problem?

For this kind of repaired device, we need to first check the place that moved before. Connect DC power supply it does not leak, the starting current stays on more than 400 mA. As shown in picture 1-1.

Considering the touch IC has been replaced, the last repairman directly took the black touch off without welding jumper wire on touch M1 pin(6P can still boot normally without installing black and white touch), but the current is same as before, measuring the starting voltage we find the iPhone 6 Plus NAND 1.8V and I2C bus 0.6 V, so we doubt it is the iPhone power IC problem. With the power on, it is indeed hot, with 400 degrees we quickly take the power IC off, according to the symptom, it's necessary to confirm whether the power supply IC is damaged, a good method is to measure the pin resistance. 1-2

1-3

The results of this 6P is measured as the power of IC to 1.8V white touch power supply is short-circuit, now it can be judged that 1.8V power supply short circuit pulled down the power of NAND and bus, removing the white touch chip, short circuit fault is solved now, welding jumper wire on black touch M1 and replace new chip, the iPhone 6 Plus is successfully fixed here. 1-4