Remove the screen and disconnect the battery. Measure diode values of pin 26, 24, 22, 20, 18, and 16 on J8000 with diode mode of the multimeter. Pin 24 and 18 have no diode values. The normal value should be around 400-500. It can be preliminarily judged that the circuits of the two pins have open circuits.

Since relevant components of the two pins are under the shielding cover, we need to remove the shielding cover. Protect the connectors with high-temperature tape.