HUAWEI Mate 40 Pro can't connect WiFi and Bluetooth

HUAWEI Mate 40 Pro can’t connect WiFi and Bluetooth

Machine model: HUAWEI Mate 40 Pro

Fault phenomenon: Huawei mate 40 Pro mobile phone Fall hard, unable to connect WiFi and Bluetooth.

Maintenance process: after getting the mobile phone, it was tested that the WiFi and Blutooth could not be connected. In addition, it was found that the mobile phone did not have flash. The mobile phone card network unstable had “no serviecs” failures from time to time.

HUAWEI Mate 40 Pro can’t connect WiFi and Bluetooth Figure 1.

Remove the machine and take out the main board. Power on the single board. Measure the Capacitor and VCC around WiFi. Measure the WiFi CLK and reset the signal to ground value. It is found that the line between WiFi chip and Crystal is broken.

HUAWEI Mate 40 Pro can’t connect WiFi and Bluetooth Figure 2.

Looking at Boardview, it is found that Crystal is on the other side of WiFi chip. Two pin Crystal directly enter the WiFi chip, indicating that there is a broken wire in the middle of PCB layer.

HUAWEI Mate 40 Pro can’t connect WiFi and Bluetooth Figure 3.

Therefore,Crystal is directly removed, and Crystal pin is connected with WiFi connection point by wire, and the wiring is fixed.

HUAWEI Mate 40 Pro can’t connect WiFi and Bluetooth Figure 4.

After testing Jump wire, it was found that WiFi was connected. Because it was a fallen motherboard, the middle layer of the main board was directly separate. After the welding was re installed into the mobile phone, all functions of the mobile phone returned to normal after the test again. The failure was repaired and the maintenance was over.