Lenovo E41 notebook does not turn on rpair

Machine model: Lenovo E41

Fault phenomenon: notebook no booting

Maintenance process: Unplug the auto power off cell and connect it to the power supply. Press Switch to find that the current is 0.01, and then it falls down. Looking at this phenomenon, you can know that it is switch Current protection.Dismantle the machine, hit each Inductor diode value, found no problem, button the battery discharge, and then press Switch, the current even blew up, full of joy to install, wait until the computer is installed, press Switch and do not open, what is the situation?

Remove the board and start the machine. After many attempts, there is no problem. It seems that the problem lies in the equipment.Through investigation, it was found that switch,Current protection,multimeter,VCC and diode value had no abnormality as long as the screen was connected. Was the screen broken?

Remove the screen and find no problem in each Capacitor. Connect the screen cable connected to the motherboard, and pull out the line connecting the screen and Camera to exclude the Current protection caused by Camera or screen.

It is found that Current protection will occur in both Camera and unplugged screens. That is to say, it is neither caused by the screen nor caused by Camera.So pull out the connection screen and the camera side and return Current protection. In this way, it can be determined that the screen cable problem caused switch Current protection.

Through the disassembly and assembly of the screen line Measuring diode value, it is found that the screen line 40 pin is directly covered by the screen line 40 pin without the screen line 380, the screen cable Short circuit and Solder Mask.