iPhone X does not turn on, power leakage 700mA for repaired

Machine model: iPhone X
Malfunction: no booting,Connect the power supply short-circuit current 700MA.

iPhone X does not turn on, power leakage 700mA for repaired figure 1.

Maintenance process:Connect the power supply short-circuit current 700mA or so, motherboard VCC has Short circuit.Connect the power supply Touch the motherboard with high temperature. Measure that the main VCC and battery VCC are normal to the ground diode value.

Connect the upper and lower VCC of the motherboard to the upper short-circuit current and the lower one is normal. Determine that the fault point lies in the lower layer. Smoke the lower layer with VCC.Connect the power supply found that Connect the power supply 17001 on U3100 had melted.

iPhone X does not turn on, power leakage 700mA for repaired figure 2.

Looking at the drawings, we know that this chip is VDDBOOST boost.

iPhone X does not turn on, power leakage 700mA for repaired figure 3.

iPhone X does not turn on, power leakage 700mA for repaired figure 4.

According to the previous 7 generations, the maintenance of this chip Short circuit was not caused by the chip Short circuit itself, but by the filter Short circuit Short circuit on PP_VDD_BOOST Related circuit, and the culprit was revealed by adding 4V Capacitor to PP_VDD_BOOST alone.

iPhone X does not turn on, power leakage 700mA for repaired figure 5.

Colophony (Solder)on C3112 melted, and diode value returned to normal after removal. Solder back the upper and lower layers of the motherboard, and repair the fault by starting the test.