Line across LCD

[Cookie Guru]

I picked up a used T61 last week. There were only two problems: the fan was noisy and needed to be replaced and sometimes I get a 2 pixel line spanning the screen horizontally. I tried to get a picture but I can't recreate it at the moment. It's a medium gray, close to #CCCCCC and is maybe 200 pixels from the top.

Replacing the fan wasn't too difficult, but this line had me stumped for a bit. Finally I nailed it down and found out that it's not a very serious problem. The line does not appear all the time and seems to show up randomly. It does not appear on external video, so the problem isn't the video "card". I found, accidentally, that I can get it to go away by tilting the screen. So my guess is that it's the video cable--93P4391.

Since I can "fix" this really easy by adjusting the angle of the screen, I'm not to keen on replacing parts in the near future. Not because they're expensive, but because it's an ordeal and a half just to get to the cable. But in case this gets worse in the future--does everyone agree with my diagnosis of it being the cable? Or am I overlooking something?

[Harryc]

It's the LCD. It has a bad row driver.

[Cookie Guru]

Any links that can help me learn more about row drivers? Google is only showing me datasheets and sales brochures.

[rkawakami]

Wikipedia should have something on LCD construction but here's a basic synopsis: Each row (and column) in an LCD panel has a transistor that controls whether it's on or off. If the transistor doesn't switch properly, then you get a "dead" row or column. There's nothing you can do to fix it other than replace the panel.

[Cookie Guru]

If it's a bad transistor, why does adjusting the angle of the panel "fix" it?

[Harryc]

Moving the LCD makes/breaks the connection on the transistor. It's like a loose solder joint.

[rkawakami]

Pressure on the electrical contacts to whatever is controlling the signal to the panel. Most likely you could induce the same repair by pressing along the edges of the panel. I don't think that the problem exists in the LCD cable as that would involve more than just a couple of rows.

[Brad]

With these failing LCD's that look as described I have never seen the cable be the problem. Always replacing the LCD fixed the problem which was a surprise. While changing the LCD angle mostly reproduced the trouble at least one LCD that failed like this started after an unexpected ThinkPad rodeo when my foot caught the A/C cable and flung the unsuspecting ThinkPad onto a carpeted floor.

Of course your mileage may vary.

Brad

[misfit]

Pressure on the electrical contacts to whatever is controlling the signal to the panel. Most likely you could induce the same repair by pressing along the edges of the panel. I don't think that the problem exists in the LCD cable as that would involve more than just a couple of rows.

Hi Ray. I really wish that this sort of thing was repairable. the best FlexView that I have, (better than the T60 FVs) a T43 SXGA+ has developed a vertical single-pixel (I think) line of stuck blue/green colour. I was told that squeezing the glued-on strip at the top might fix it or, if not, applying heat to the area and compressing it.

I've tried dismantling the lid and squeezing it but it's made no difference. I'm not prepared to heat it just yet as I'd rather have it as-is as a 'hack' machine than destroy it completely. (To me a FlexView with a stuck line is better than a mere TN XGA panel, which is my only option right now.)

When 'times' are better I might look for a replacement FV but for now I'll just use it without my glasses on. What I find odd is that it 'just happened'. The machine was left on a desk, one day it was fine, the next it wasn't. I could understand it if it'd been slapped around a bit or something.

Cheers,