Open Xinzhizhao software, find a circuit reference of mobile phone motherboard using Hi1102V100, measure the power supply according to the schematic diagram, and replace a WiFi chip, and the fault remains.
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 enjoys 20SE maintenance without turning on the water. By looking at the bitmap of Huawei Enjoy 20 SE motherboard in Xinzhizhuang software, it is found that there are many components and chips connected to the main power supply. The…
There is a resistor corrosion on the motherboard, so directly remove the corrosion resistor and make a short circuit. After power-on test, the mobile phone WiFi can be turned on normally and the fault can be repaired.
Check the small board and find that there is corrosion next to the microphone. Remove the chip, clean the pad and redo the filter next to it. Boot test, perfect repair.
Machine model: Glory X30i
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 measured capacitance of corrosion at startup is 1.8V, and the measured capacitance is 2.4V This circuit is connected to the signal chip of the main board, the upper board and the tail plug-in board. Redo this chip, and the power-on test voltage is restored to 1.8V. Boot test, perfect repair.
HUAWEI Mate 30 has no sound after connecting Bluetooth. After making up the phone, the WiFi chip is replaced, and the fault is fixed.