IPhone XS Max phone screen intermittently does not show repair

First, replace the screen. After replacement, the fault remains the same. Check the PCB wiring position through the wiring diagram of Xinzhi Manufacturing Board Layer. Scrape the PCB board, reconnect the lead of PMU_TO_DISPLAY_RESET_CONN_L, and repair the fault.

Machine model: iPhone XS Max

Malfunction: the screen of the mobile phone does not display intermittently.

Maintenance process:

I received an iPhone XS Max, and the fault description shows that the screen of the phone appears intermittently.

After getting the mobile phone, all functions of the boot test are normal, but the screen will appear intermittent and not displayed. This fault should be caused by an abnormal line connecting the display seat.

First, replace the screen. After replacement, the fault remains the same. Open the annotation map, point bitmap and schematic diagram of Xinzhi.

IPhone XS Max phone screen intermittently does not display maintenance figure 1

Find the connecting seat of the display screen and measure the resistance of each foot of the seat. It is found that the resistance value of PMU_TO_DISPLAY_RESET_CONN_L line is unstable at the fifth foot of the seat. Make sure that the wiring of the circuit board layer is broken.