Redmi Note 9 Pro touch screen failure

Redmi Note 9 Pro touch screen failure

Machine model: Redmi Note 9 Pro

Malfunction: Redmi Note 9 Pro can boot normally, but the touch screen of the mobile phone fails.

Maintenance process: After getting the mobile phone, turn it on for testing, and the touch of the mobile phone screen fails. This situation is usually caused by screen damage or insufficient conditions provided by the motherboard.

Redmi Note 9 Pro touch screen failure Figure 1.

Remove the main board from the machine, and measure the ground value of the display touch pad with a multimeter. It is found that one of the data lines has a resistance value of OL, and the data line of the display touch pad leads directly to the CPU, which indicates that the CPU is virtually soldered.

Redmi Note 9 Pro touch screen failure Figure 2.

So remove the CPU and redo it.

Redmi Note 9 Pro touch screen failure Figure 3.

Then put the motherboard back into the phone. After the phone is turned on, the screen touch is normal, and the fault is perfectly repaired.

Redmi Note 9 Pro touch screen failure Figure 4.