After Lenovo G40-30 fell, the notebook could not be turned on for repair

After Lenovo G40-30 fell, the notebook could not be turned on for repair.

Replace the EC, and then measure 3V to the ground. Everything is normal. Power on for about 0.02, the external monitor tests that the current of about 0.36A has turned on the machine, and after installation, it turns on the machine for about 0.6A without plugging in the battery. Troubleshooting, the maintenance is over.

Model: Lenovo G40-30

Main board version number: NM-A311 REV:1.0

Malfunction: The notebook can’t be turned on.

Maintenance process:

Connected to a Lenovo G40-30 laptop, it can’t be started after falling.

Lenovo G40-30 notebook can’t be turned on after falling. Maintenance Figure 1

The bare ammeter is inserted into the board, and the standby time is about 0.16. Take out the thermal imaging, and the EC heats up. The power supply of EC mainly comes from the standby chip. Check the standby inductor first. 5V is normal to the ground, and 3V is short-circuited to the ground. Remove the EC, measure the ground value of more than 300, and measure the other inductors again. The resistance value is normal.

After Lenovo G40-30 falls, the notebook can’t be turned on. Maintenance Figure 2

After Lenovo G40-30 falls, the notebook can’t be turned on. Maintenance Figure 3

Replace the EC, and then measure 3V to the ground. Everything is normal. Power on for about 0.02, the external monitor tests that the current of about 0.36A has turned on the machine, and after installation, it turns on the machine for about 0.6A without plugging in the battery. Troubleshooting, the maintenance is over.

After Lenovo G40-30 falls, the notebook can’t be turned on. Maintenance Figure 4