Lenovo E41 notebook does not start repair

Machine model: Lenovo E41

Fault symptom: the notebook does not turn on.

Maintenance process: unplug the battery and connect it to the power supply, press the switch and find that the current is 0.01 and then it falls. Look at this phenomenon and you will know that it is trigger protection. Disassemble the machine, hit the resistance of each inductor, and no problem was found. The battery was discharged and then the switch current was pressed, and it was brushed up with joy. When the computer was installed, the switch was not turned on. What happened?

The detached single board can be turned on, and there is no problem after many attempts. It seems that the problem lies in the equipment. Through investigation, it is found that the protection will be triggered as long as the screen is connected, and there is no abnormality in the power supply resistance of the multimeter when it hits the 3.3V 19V screen. I wonder if the screen is broken.

Remove the screen and measure the capacitors. No situation is found. Connect the screen wire connected to the motherboard side, and unplug the wires connected to the screen side and the camera side successively to rule out whether the camera or the screen causes protection.

It is found that no matter whether the screen is unplugged or the camera is protected, that is to say, it is not caused by the screen or the camera. So unplug the connection screen and the camera side and protect it, so that it can be determined that the screen line problem caused the trigger protection.

By disassembling the screen wire and marking the value, it is found that the screen excuse is the 40th pin, the screen wire 380 is not installed, the screen wire is short-circuited, and the green oil directly covers the 40th pin of the screen wire.

Lenovo E41 Notebook Maintenance without Booting Figure 1

Blow dry, connect the screen, press the switch to start the machine normally, install the machine normally into the system, and the maintenance is over.