Repair of Lenovo ThinkPad E540C notebook when it is turned on or off

Repair of Lenovo ThinkPad E540C notebook when it is turned on or off.

Lenovo ThinkPad E540C notebook is powered on and powered off. After removing the capacitor, the measured resistance value is more than 300 ohms (the one after disconnection). After the capacitor is installed, the computer will be normal.

[machine model] Lenovo ThinkPad E540C notebook

[motherboard version number] NM-A211

[Fault phenomenon] The notebook is powered on and powered off.

[maintenance process]

Upon receiving the Lenovo E540C fault machine, the motherboard version number is NM-A211, and the startup current rises from 0.5 to 0.7, it will be powered off and shut down. At first, I think it’s a BIOS problem, whether the BIOS is brushed or the power is turned off.

Lenovo ThinkPad E540C notebook power-on power-off fault maintenance Figure 1

Check the power supply except the power supply of the video card. Measure the resistance of the power supply inductance of the video card to the ground to 0 ohms. Disconnect the rear connection point, and the measured resistance is also 0 drive.

Maintenance of Lenovo ThinkPad E540C notebook when it is turned on or off.

Maintenance of Lenovo ThinkPad E540C notebook power-on and power-off failure Figure 2

Someone in the forum said that the power supply capacitor of this machine’s graphics card has a short circuit, which is a common fault. After removing the capacitor, the measured resistance value is more than 300 ohms (after disconnecting). After the capacitor is installed, the computer will be normal.