Xiaomi 161201-AA notebook does not start for repair

After checking, there is an indicator light on the inserted charger, and there is no boot response when the power-on key is pressed, but the indicator light will go out when the power-on key is pressed, which may trigger protection due to local short circuit. It is found that many capacitors are short-circuited. After removing the short-circuited capacitors, test the other capacitors to ensure that they are not short-circuited. After commissioning, 3.3V returns to normal.

Machine model:Xiaomi 161201-AA notebook

Malfunction: The notebook does not boot.

Maintenance process:

Received a Xiaomi 161201-AA notebook, and the fault description notebook can’t be turned on.

When the machine is disassembled, it is found that the 19V voltage is normal, the charging voltage is normal, and the 5V voltage is normal. All peripheral devices are disconnected for testing, but there is no response when the machine is turned on. Basically, the problems of power interface TYPE-C and voltage conversion are eliminated.

After checking, the indicator lights up when the charger is inserted, but there is no startup response when the power-on button is pressed, but the indicator will go out when the power-on button is pressed. It is judged that the machine has startup action, which may trigger the protection due to local short circuit.

Xiaomi 161201-AA notebook does not start for repair

Xiaomi 161201-AA notebook is not turned on for maintenance Figure 1

Measure each power supply capacitance with a multimeter. After inspection, it is found that the capacitors in the red circle in the following figure are in short circuit state, and the number is a bit too much, so it’s necessary to burn the machine.

Xiaomi 161201-AA notebook is not turned on for maintenance Figure 2

Find the short-circuit DC-DC power supply, adjust the adjustable power supply to 1V, and turn on the electricity to burn the machine. It is found that a capacitor next to the sound card is hot seriously.

After removing the short-circuit capacitor, test that other capacitors are no longer short-circuited, and power on the test machine, and 3.3V returns to normal.