WiFi chip has been repaired at home. The power supply of the WiFi chip is normal when it is turned on, so the iron case of the crystal oscillator is directly found. After disassembling it, the crystal oscillator is taken down to measure the ground value of the crystal oscillator, and it is found that the two ground wires of the crystal oscillator are dropped. Find a good 38.4MHz crystal oscillator and put the motherboard back inside the phone.
Huawei Mate 30 Pro screen does not display, and the motherboard is installed in another screen assembly for testing, but the screen still does not display, so it can be determined that it is a motherboard problem.
Measuring the resistance value of one end of C1226 main power supply is also about 400, basically locking the main power supply or middle layer virtual welding. Welding the main power supply in layers. Start-up test, there is a signal, and the maintenance is over.
The resistance value of one end of C1226 main power supply is also about 400. The main board has been changed, and it must have fallen before. The main board has no deformation area, so the main power supply is basically locked or the middle layer is soldered.
HUAWEI Mate 30 Pro couldn't connect to WiFi. It was found that two GND of Crystal were dropped. After replacing Crystal, the fault was fixed.
HUAWEI Mate 30 Pro screen does not display, AMOLED is found in the test_There is a problem in the connection between avdd and Capacitor. Remove the problem Capacitor and repair the fault.
NO booting hanging the screen of HUAWEI Mate 30 Pro, replace the decryption battery and repair the fault.
Huawei mate 30 Pro mobile phones no serviecs and Jump wire are supplemented, and the call is normal.
Huawei mate 30 Pro mobile phone has no signal,separate Repeat welding main power supply makes a homing action, power on test, fault repair.
