Then we separate the motherboard. Put the motherboard on the 160 °C Heating Platform to heat. After about one minute, remove the logic board and signal board with tweezers. It can be seen that the motherboard has been separated before.

Open the bitmap. The other end of the resistor is connected to the power IC through the middle layer. Therefore we need to measure the circuit on the logic board firstly. The value of resistance is normal.

Then we measure the circuit between the signal board and the touch connector. The value of resistance is 1