Huawei Honor 9x Pro cannot be charged for repaired

Machine model: Huawei Honor 9XPro

Malfunction: The mobile phone can’t be charged.

Maintenance process:

I received a Huawei Honor 9X Pro. The fault description is that Camera can’t lift. I can lift after I remove the two resistors next to U2803, but after that, the phone can’t be charged.

After the startup test, all functions of the mobile phone are normal, and lighting cable is plugged in without prompting for charging.

Open Xinzhizao Soft, find Honor 9XPro Boardview, and find u2803. According to Boardview, the resistors R728 and R729 were removed.

Huawei Honor 9x Pro cannot be charged for repaired Figure 1.

These two resistors, one end of which is connected to U2803 and CPU, and the other end of which is power chip 1.8V VCC, are signal pull-up resistors.

Continue to open schematic to check U2803, and find that the U3803 and CPU lines connected by these two resistors are I2C4 data and CLK lines.

Huawei Honor 9x Pro cannot be charged for repaired Figure 2.

Remove these two resistors, that is, lower the high level of I2C4, which makes it impossible for CPU and chip to communicate. On the other hand, A1 and C1 pin of U2803 are the CC detection pin bits of the USB interface, which makes it impossible to detect after USB is inserted, which leads to the inability to charge. Make up 1K resistor and repair the fault.