iPhone6 Press the start button without reaction repair

Machine model: iPhone 6
Fault phenomenon: press the power on button and there is no response
Maintenance process:

Received an iPhone 6, the fault is that the phone does not respond by pressing the start button,Won’t Turn On.

Measure the power on key 1.8V without VCC, and measure the ground with diode value OverLoad.After checking Boardview, we can know that the power on key is connected with fl0809, the back end of fl0809 is connected with Connect the power supply source chip and CPU, and the back end of Inductor is also OverLoad.Remove the power chip and find that PAD has pad break off.

iPhone6 Press the start button without reaction repair Figure 1.
According to the drawings,pad break off are all GND points, and there is no need to make up. The power chip switch 200mA is not online. Because Nand was repaired,Nand was removed and PAD was found to have Short bridge.

iPhone6 Press the start button without reaction repair Figure 2.
After processing the PAD and switch 60mA, the current of DFU is normal, but it is not connected to the machine when the lighting cable is inserted. When measuring the charging connector seat, pp5v0 is found_USB to the ground, observe the shielding cover above the Baseband power supply has traces of welding.After removal, it was found that there was a small tin bead between c1470 and c1740. After removal,Diode value is normal was measured and lighting cable was inserted into it, and it was on-line normally.

iPhone6 Press the start button without reaction repair Figure 3.
When Nand is replaced, the startup current of switch is normal, and other functions are normal.