The charging of Huawei P20 mobile phone is abnormal, indicating that charging is not allowed for repair

In this case, the voltage output of capacitor c1610 in the measurement schematic diagram is abnormal, so coil L1600 should be excluded first, and U1602 should not be replaced.

Machine model: Huawei P20

Fault performance: it shows that charging does not work.

Maintenance process:

A Huawei P20, the mobile phone is charged abnormally, indicating that it cannot be charged.

Huawei P20 mobile phone is charging abnormally, indicating that it will not be charged. Figure 1 shows maintenance.

Measure that the charging 5v input to the motherboard is normal, and then find that the position input of the charging IC is normal, and the output voltage is only a few tenths of volts. It is suspected that there is something wrong with the charging 5V input and the charging IC output.

Huawei P20 mobile phone is charging abnormally, indicating that it will not be charged for maintenance. Figure 2

First remove the coil at the output end, and find that one leg of the coil has peeled off, and decisively replace it.

Power-on test found power-on leakage, temperature sensing method was used to determine the approximate heating area, and rosin method was used to lock the heating point. As shown in the figure, the charging IC melts instantly. Replace it with a new charging IC, and the fault is solved!

Huawei P20 mobile phone is charging abnormally, indicating that it will not be charged. Figure 3 shows maintenance.

Generally, it shows that charging does not lead to electricity. It shows that charging means that the voltage input is normal. What we are considering is the voltage output or the battery detection pin, which need specific measurement.

Huawei P20 mobile phone is charging abnormally, indicating that it will not be charged. Maintenance Figure 4

In this case, the voltage output of capacitor c1610 in the measurement schematic diagram is abnormal. Check that the principle voltage is output by VCHG USB through U1602 and L1600. According to the principle of simplicity to complexity, the coil L1600 should be excluded first, and U1602 should not be replaced. Just lock the target and coil it!