iPhone 7 7P Repair: Boot Failure & Power Leakage

The battery voltage VBATT is firstly sent to the iPhone 7 charging IC, it outputs the main power PP_VCC_MAIN and then supply to the power supply IC and other related circuits. When the power button is pressed, the IC output voltage of the power supply is supplied to iPhone 7 CPU, NAND and other related circuits respectively. The battery voltage VBATT and the main power supply VCC_MAIN are sent to the relevant circuit before turning on the iPhone 7, in this case, if there is power leakage or large current when connecting with DC power supply, it means that either the battery voltage VBATT or main power fupply PP_VCC_MAIN has short power leakage component. There are plenty of components are connected with these 2 circuit, use rosin will help you to find the damaged one quickly.

Specific methods are as follows:

1. Measuring the of the grounding resistance of the iPhone 7 battery voltage and the main power supply to find the short-circuited part

2. Use rosin to smoke the iPhone 7 motherboard parts into white color

3. Then add voltage in the short-circuited part, the voltage will gradually increase from zero, after a while, the short-circuited part will heat and rosin will melt, so you will see it immediately.

Note: It is very important to master the rosin method because of there is a lot of power leakage or large electric current.

Looking for more cell phone repair skills , check on www.vipfixphone.com

More cell phone repair tutorials read at www.vipfixphone.com