I have a laptop that has been having problems with the display for months. I can see the images on the screen (especially with a flashlight) but the display is very dim.
At first the problem was that whenever the laptop went into the sleep state the screen would stay dim even when awakened. If I closed the lid and re-opened then the screen would light for a little while. Eventually it stayed lit so long as the computer didn't go to sleep. I stopped the computer from going to sleep at all and this solution worked for a few months.
But now the light has gone out again regardless of the sleep state. When I power on the computer or close and re-open the lid, the display becomes bright for about half a second but that's it. I disassembled the display and couldn't find any loose or untoward connectors. The inverter and everything looks okay. I think the sleep switch is magnetic so I can't mess with that (I have yet to find it). I can't figure out which component is causing the problem so I don't know what to replace.