problem with intermittent LCD going dark; logic or analogic?

[Klaus Greeff]

Hello anybody
System: I am a happy user of an A21p (2629-HWG, 1600x1200 TFT, W2K about 4 -5 years old.
Problem: Since about 2 months LCD goes black repeatedly 1-2 h after start from cold. External monitor continues to work. Switching Fn,F7 through 3x recovers LCD to full brightness, but after 5 - 10 minutes black again.
Tried so far: For logical faults: Power management and monitor settings. Updated BIOS, Video driver and Power management to newest version. No succes.
Suspect analog problem: Does anybody know whether there might be a heat sensitive element which might now switch too early the LCD off; or the fan might not cool such an element well enough. Is it at all possible to reach to such a level into the interna of a notebook?

Many thanks for suggestions.
Klaus

[supportsquakmt]

I had this problem.

I fixed it by opening up the laptop lid and :
1. re-seating the cable that goes to the back of the lcd at the lcd end.
2. The inverter card was loose, and it looks like the screw that holds it to the lid might provide its connection to ground. I tightened it.
3. re-seating the cable that goes to the back of the lcd at the motherboard end.



Good luck !

[Klaus Greeff]

Fine to get an answer! Before finding out about the Hardware maintenance handbook for the A21, I just could not resist to start opening what I could find - my heart trembling.

I opened (batteries, power off) the screws around the LCD frame because I did not know that the hinge could be uncovered - it is all so well made.

So I could see the flat cable and its seating and the inverter card. My interest to understand what an inverter card might be good for kept me searching internet pages for hours after reassembling my machine.

It still goes dark and I found the screw that holds the inv. card well fixed. Of course, it was all a bit narrow and I possibly should repeat it the handbook way - but how long will this procedure last?

What I observed though:

1. Before putting back the screws around the LCD sandwich which I only loosly readjusted, I could run the machine with a bright screen for more than an hour; actually I was already hoping things were cured. But after tightenïng all screws, i.e. pressing the sandwich together again, the old problem came again.

2. May there still be something heating up? E.g. the inverting card, because it sits directly squeezed under the black frame at the lower end of the LCD? I tried today to check whether the going black of the LCD might be postponed when I set the brightness down. This works! But with a dim screen.

Now? Can anybody explain to me briefly whether the inverting card could warm up (every element when working does so, I suppose) and might suddenly change its behaviour such that the back-light is minimal. In fact, the screen gets dark but a faint structure, probably the TFTs seen under ambient light, remains showing that the control of the TFTs works but the light is missing.

Would it be reasonable to change the inverting card?

Many thanks for helpful and introductory comments to a curious novice who has a bit experience with electronics.

Klaus