iPhone XS Max Face ID can't be repaired by failure

iPhone XS Max Face ID can’t be repaired by failure

Malfunction model: iPhone XS Max

Malfunction: the face ID cannot be used.

Maintenance process:
The customer described that,mobileFace ID can’t be used. Enter Face ID to prompt Face ID ID to be unavailable. You can set Face ID ID later after iPhone cools down.

iPhone XS Max Face ID can’t be repaired with fault Figure 1.
According to the prompt,Face ID can’t be used because of too high temperature. If the temperature is too high, it is very likely that there is Short circuit, and the temperature control detection circuit detects an abnormality. So that the function cannot be used. Then we disassemble the machine to check whether there is Short circuit, disassemble the machine, connect DC power supply to start up and find that switch 288 mA jumped, which seems to be the correct judgment.Where there is Short circuit.

iPhone XS Max Face ID can’t be repaired with fault Figure2.

In the test, it was found that switch was normal without connecting the screen.

iPhone XS Max Face ID can’t be repaired with fault Figure3.
Then the fault point is on the screen or earpiece FPC. It is found that the jump-off current is abnormal when connected with earpiece FPC. When earpiece FPC is removed, it is found that the sealant on resistor earpiece has burned yellow.

iPhone XS Max Face ID can’t be repaired with fault Figure4.
Current heating test found that an Capacitor Short circuit was damaged. Pick it off directly with tweezers, open Xinzhizao Soft, and check the point position. This filter Capacitor is on the line of PP3V0 _ YOGI _ PROX _ ALS _ Conn VCC.

iPhone XS Max Face ID can’t be repaired with fault Figure5.

iPhone XS Max Face ID can’t be repaired with fault Figure6.

Next, we install the test.

iPhone XS Max Face ID can’t be repaired with fault Figure7.

Face ID is back to normal, functioning normally, and the maintenance is over. The fault is caused by the damage of filter Capacitor Short circuit of pp3v0 _ yogi _ prox _ als _ conn VCC on earpiece FPC.