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My Lenovo was dropped and had a shattered screen, but worked when connected to an external monitor. I ordered a replacement screen and installed it. I did not, however, remove the battery before installing the new screen. Now the new screen seems to have no backlight. I can see what is on the screen when I shine a light on it, and it still displays on an external monitor. I reconnected the old screen and had the same results. So I am assuming it is not the lcds themselves. I am a novice and am needing some help as to what my next step should be in troubleshooting this issue.
Hi @aphe , You most probably have blown an onboard fuse in the backlight power supply circuit or hopefully it may be more simple than that and you have accidentally broken the backlight power cable or the connection to the lid switch board. Don’t know for sure with your particular model but it may be that the lid switch board is part of the Power On/Off switch board and when the lid is closed the switch operates (it is magnetically operated) to send a signal to turn off the power to the backlight. Whatever the problem the best way to find it is to use a schematic diagram of the motherboard to help you locate what is wrong Unfortunately the best that I can find to help you with this, is this link where you can purchase a schematic of the motherboard which should help you, as the block diagram on the page doesn’t give too much detailed information. If you haven’t already got one, a DMM (Digital MultiMeter -adequate ones are available from larger hardware stores for about $15-$20) would be a very handy tool to have to help you with this problem At least you now know to always disconnect the power supply, be it AC or DC (or both) whenever you are literally repairing electronics. It saves a lot of potential electrical problems from occurring e.g slipping screwdriver shorting out something, not mechanical problems though e.g. accidentally removing SMD components from the motherboard e.g. again slipping screwdriver or other tool Good Luck!
