iPhone x face ID unavailable for repair

Malfunction model: iPhone X

Symptoms:Face ID id is unavailable and not charged.
The customer described that the charger plugged into charging connector can listen to music without charging, even connected to Connect the power supply brain, and the wireless charging can only reach 80%, and there is no Face ID identification after changing the screen.

Fault analysis:
Wireless charging can charge up to 80%, wired charging can’t charge, and it can be connected to a computer. There may be a problem with the charging circuit. There is no Face ID after changing the screen. It may be that earpiece FPC is broken.
Maintenance process:
After receiving the phone, it can be charged by wireless charging, but it is not fully charged. Wired charging is directly unresponsive, and there is no charging icon, which can connect the Connect the power supply brain.

iPhone x face ID unavailable for repair Figure 1.

iPhone x face ID unavailable for repair Figure 2.

First of all, the replacement failure caused by Accessories is still the same. Disassemble the machine and take down the motherboard,separate, and observe under microscope that the charging Inductor has broken.

iPhone x face ID unavailable for repair Figure 3.
Remove auto power off directly and replace it.

iPhone x face ID unavailable for repair Figure 4.

After replacing Inductor, it was found that there was still no charging response on the test rack.

iPhone x face ID unavailable for repair Figure 5.

The computer can be connected to the Connect the power supply brain, which proves that the USB chip is ok, so the fault may lie in the charging chip. Replace the charging chip U3300 and the fault remains the same. Disassemble the chip and call PAD to diode value, and find A4 pin bit PP_VBUS1_E75_RVP_R to OverLoad.

iPhone x face ID unavailable for repair Figure 6.

iPhone x face ID unavailable for repair Figure 7.

This signal is transmitted to USB chip U6300 through R3360 resistor, and the other end of R3360 is measured to Diode value is normal.

iPhone x face ID unavailable for repair Figure 8.

diode value, which measured the resistance, found that it became 14.97 kOhms, and the resistance became larger, resulting in abnormal signal.

iPhone x face ID unavailable for repair Figure 9.

Just pick it off and replace it with a good 10 ohm resistor.

iPhone x face ID unavailable for repair figure 10.

iPhone x face ID unavailable for repair figure 11.

Test on the test rack, and the charging returns to normal. Next on the motherboard,welding.Face ID can’t be used in the installation test, and earpiece FPC is broken during the inspection.

iPhone x face ID unavailable for repair figure 12.

Replace earpiece FPC directly, and move earpiece FPC which has passed the distance sensing module and environment sensing module, otherwise Face ID will be repaired, and the function of earpiece will not work.

iPhone x face ID unavailable for repair figure 13.

Maintenance result:

After installation test,Face ID returns to normal, charging returns to normal, and maintenance ends here. This fault is caused by the damage of charging Inductor, no charging caused by the damage of R3360 resistor, and no Face ID caused by breaking earpiece FPC.