ThinkPad 570 - very dark screen (but not always)

[Tim320]

I've just picked up a ThinkPad 570 from a big computer clear-out that was happening near me.

The guy that gave it to me said the screen was dead and the laptop was good for parts only, but I have found that the screen is just about visible - it is just extremely dark. Tilting it at various angles to the light seems to make it slightly more readable - I can just about see Windows XP starting up and read the text on the Welcome Screen, but it is so dark that this person thought that it wasn't working at all. There's no distortion/lines or anything though, and the colours and everything look fine. I tried sliding the brightness slider to the right of the screen up and down but it seemed to make no difference.

Now for the really weird bit. I was messing around with it, just trying out powering it up a few times, leaving it on, turning it off etc. and one time that I did this, it came on perfectly, screen exactly as it should be. I think it had been on for quite a while the time before this happened (I'd just left it sitting with the dark screen to see if anything happened, then turned it off and left it for a short while, then tried it again). Then I turned it off after that, and I've put it on about 3 times since (the first time immediately after turning it off with the screen working perfectly) and it's been really dark again like it was before.

The only visible sign of possible damage is that the little bit of plastic with a dark shiny piece of material around it that can be seen at the back of the laptop when the lid is closed (it is on the screen half of the machine, and the shiny bit goes down into the computer half, just above the small flat port between the power in and the serial port) is not quite straight. The piece of plastic with the shiny bit around it is pushed further into the laptop on one side (only a few millimetres, but enough to be clearly visible when looking at it), although there's no obvious damage to this component (eg cracking or an obvious hole where the pushed-in end should fit and has come out). I don’t know if this bit is normally straight though, although it doesn't really look quite right, or whether even if this bit has got dislodged a bit it would cause the screen darkness (as both power and signal are clearly still getting to the screen).

Any ideas what might be wrong with it, and how I can go about sorting it (preferably something simple that doesn’t involve opening this thing up! - if realigning the plastic thing would help solve the problem, or anything else like that)?

Thanks

[tfflivemb2]

There are a few possibilities:

1. Loose LCD cable.
2. The inverter needs to be replaced.
3. The CCFL (backlight inside the LCD) needs to be replaced.

Try searching the forum for "backlight" and "570" and you will most likely find several posts regarding these possibilites, and some solutions that have worked. The order that I listed the above is the least costly possible fix through the most costly possible fix.

EDIT: I forgot to add, here is the Hardware Maintenance Manual that will show you how to get to and work on the part mentioned above, with the exception of the CCFL (since it is a subpart of the LCD):
ftp://ftp.software.ibm.com/pc/pccbbs/mo ... 9n8609.pdf