IBM Thinkpad R40 LCD problem

[Laundre]

I recently received an IBM R40 Thinkpad that is having backlight problems with the LCD. The computer boots up and the screen can be faintly seen. It's clearer if you shine a flashlight through from the back and it works fine if you hook it up to an external monitor.

I figured I could find the faulty part and replace it but I've replaced the LCD screen, inverter, and the LCD cable and none of them have fixed the problem. All these parts were purchased on ebay so theres always the chance that the replacement part(s) were also faulty, but that aside does anyone know anything else that could be causing the problem?

Thanks in advance!

-Chris

[Terrahawk]

How about the LCD lid switch? That may cause the backlight to not work properly.

[Stargate199]

Welcome to Thinkpads.com!

My guess would be the switch that tells the computer that the lid is closed. Usually that just turns off the backlight, but not the LCD entirely. That may need to be replaced, but it may just need repair. I don't know exactly where it is on the R40, but you will need to take the computer apart to access that part.

[Laundre]

Thanks guys! I will look into replacing the lid switch.