Laptop display not working, motherboard problem?

[waspfish]

I recently dropped my T42, and the screen went dim (you can still see a very faint image of the screen). I can still operate the computer if I hook it up to an external monitor. I sent it back to IBM for repair, they asked me to replace the motherboard, insisting that's what was causing the problem. What's the chance of this being caused by motherboard problem? I have asked them to return my laptop since but would like to find out from you all if they are lying or not.

[K. Eng]

Based on the fact that the screen went dim, but was still faintly visible, my guess is that the LCD backlight broke.

If the system board was malfunctioning, odds are that the system would not work at all. The fact that you can use the system if it is hooked up to an external display suggests that the system board may be fine.

I don't know if there is something on the system board that controls the backlight that is broken. Perhaps someone here with T4x repair experience can tell us.

It is illegal under the laws of most U.S. states for a company to represent that unnecessary repairs need to be done.