Maintenance of Lenovo G40-30 Notebook no booting

Machine model: Lenovo G40-30

Main board version number: NM-A311 REV:1.0
Fault: plug in no power on

Maintenance process:

I received a Lenovo G40-30 laptop, but it didn’t turn on after falling.

Lenovo G40-30 Notebook no booting Maintenance Figure 1.

Insert DC power supply into bare board, stand by 0.16 or so, and take out thermal imaging, EC high temperature. Ec VCC mainly comes from the standby chip, first check the standby Inductor,5V to ground is normal, 3V shorted to ground. Remove the EC, then measure the ground value by more than 300, and measure the other Inductor again,Inductor.

Lenovo G40-30 Notebook no booting Maintenance Figure 2.
This EC is built-in program.

Lenovo G40-30 Notebook no booting Maintenance Figure 3.
Replace the EC, and then measure the 3V ground. Everything is normal. The power-on standby is 0.02 or so. The external display tests that the current of 0.36A or so has reached or so. After installation, it is not plugged into the electric pool 0.6A or so or so. Troubleshooting, maintenance ends here.