Lenovo ideapad 15 2020 computer does not trigger maintenance

Lenovo ideapad 15 2020 computer does not trigger, wind gun, add welding once, cool after testing 5V normal output.The trigger system doesn’t power down.Long time test is normal, repeated power on and shutdown is normal, repair is over.

Machine model: Lenovo ideapad 15 siil2020

Board No.: nm-d031

Fault phenomenon: not triggered

Maintenance process:
1. Plug in the power, the current is 0.8, the charging is normal, and it is not triggered

2. Remove the machine and pull out the battery. The standby current of the bare board is 0.02, sometimes 0.009Press the switch to trigger normally and start the machine normally.About one minute after entering the system, the power will be cut off automatically, and it can not be triggered again.Power off, and then power on, can trigger boot into the system, and then automatically power off.

Lenovo ideapad 15 2020 computer does not trigger maintenance Figure 1

3. Thought it was caused by high temperature.Check the temperature is OK, the machine is not hot.Remove the temperature problem for the time being.

Lenovo ideapad 15 2020 computer does not trigger maintenance Figure 2

4. When the automatic power failure does not trigger, measure whether the standby voltage is off.It was found that 3V was normal, 3vpg was only 2.9v, 5V was abnormal, only 2V.If the pu5ic is turned on, the output of the pu5ic is normal.The air gun should be welded once more. After cooling, the output of 5V is normal.The trigger system doesn’t power down.Long time test is also normal, repeated boot and shutdown is normal, it is repaired.

Lenovo ideapad 15 2020 computer does not trigger maintenance Figure 3