T23: Display distorted and wrong colours. External RGB ok.

T2x/T3x series specific matters only
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Shurato
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T23: Display distorted and wrong colours. External RGB ok.

#1 Post by Shurato » Tue Mar 25, 2008 3:52 pm

Hello all

The subject line sums it up in a most brief possible way :D
On behalf for someone I'm posting this question, what to fix when the TFT display starts to flicker randomly and distorted and shows wrong colours? Occasionally it shows the imagine fine again; which would lead me to think about an issue of a loose contact somewhere.
If it'd be relatively easy to fix it, I would attempt it.
The question however is, what it would be; if it would be an issue of a loose contact (and which one it would be) the display itself or the inverter - or another element which would need replacement?
I was figuring out that it's most likely unlikely to be the graphic card, since when connecting an external display, the image is being shown just fine.

I have a functional T21 I could use for spare parts and I was wondering if the display-elements are hardware-compatible with the T23?

Any tips and advices are very much appreciated.
IBM TP 770, 160 Mbyte RAM, OS/2 Warp 4
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IBM TP 600, IBM TP240, 2x T21, 2x T23, quite a few coming and going :-)

SMA
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#2 Post by SMA » Tue Mar 25, 2008 4:51 pm

In my opinion, most likely the lcd cable. It can be the panel. It is unlikely to be the inverter.
You can take the easy path and swap the entire lcd assemblies between the t21 and the t23.
The lcd cables in the t21 and t23 does not look the same but they are compatible - assuming they are both having 14.1" panels.

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#3 Post by ajkula66 » Tue Mar 25, 2008 5:30 pm

I'm going to assume it's the graphic card. The external output is analog, whereas the internal one for the LCD is digital, and one has nothing to do with the other.

If it's not the cable, which may also be the culprit, than it's definitely the motherboard.

Good luck.
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#4 Post by tfflivemb2 » Tue Mar 25, 2008 7:27 pm

Depending on the model type numbers, you should be able to swap the displays. A regular 14.1" XGA LCD from a T21 will work just fine in a T23 that also uses a 14.1" XGA LCD.

I have easily interchanged T21 and T23 Displays and LCDs.

The biggest issue is making sure that they are the same size (ie. 14.1 and not 13.3" LCDs) and resolution.

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#5 Post by Robbyrobot » Wed Mar 26, 2008 3:01 am

Just to muddy the waters a little more :wink: , I might suggest removing the keyboard and palmrest, unplugging the display and cleaning around the display socket on the mainboard with an old toothbrush and isopropyl alcohol.

I have a T21 mainboard that provided a good signal to an external monitor, but would not run the backlight on the internal display. I checked this with several displays, all of which had good backlights when run on other boards. Finally concluded that the mainboard was defective.

A couple of days ago, I started playing with this board again and cleaned the display socket as indicated. After drying the area, the problem with the backlight not lighting had disappeared completely. I now suppose there was some dirt causing a current leak or short, and that I washed this out with the cleaning operation.

So if nothing else helps, you might try cleaning the socket as mentioned. This is simple, not much work and if it helps could save you a lot of trouble.

Shurato
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#6 Post by Shurato » Thu Apr 03, 2008 6:37 pm

Thanks to all for the helpful hints and tips

The first attempt I did was to clean around the connector with isopropyl-alcohol as suggested where the display is connected. It seemed to help somewhat; the display still turned white, though for a shorter time and these distorted colours did not appear.
So eventually I replaced the LCD-bezel by one from a spare T21 and - hey presto - this seems to have done the trick. So far no flicker and white screen :-)
I wonder if this screen-turning-white-issue is due to a loose contact from the cable to the inverter or inverter to display - or something along these lines; anyone any idea? Anyhow, the issue must be inside the LCD-bezel; could narrow it down that far.
Since other than that, when the display shows the desktop, it just looks fine. The client to whom the T23 actually belongs said it is like there's an element overheating and making it turn white.
Anyhow, will be using that "faulty" display on the T21 to experiment; possibly taking it apart first and clean the connectors thoroughly.

Other than that, it actually was my first "more serious" Thinkpad disassemble and reassemble project - actually it was much easier than I thought. Also thanks to IBMs excellent Hardware Maintenance Manual.
IBM TP 770, 160 Mbyte RAM, OS/2 Warp 4
IBM TP 770ED, 128 Mbyte RAM, WinXP
IBM TP 600, IBM TP240, 2x T21, 2x T23, quite a few coming and going :-)

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#7 Post by flo2323 » Sat Jun 07, 2008 4:58 am

Hello,

Im new to the forum and found this thread.
I have exactly the same problem with my T21-Laptop (it is a 2647-27G with a - according to the Lenovo parts information - 13.3 XGA(1024x768) TFT LCD.

After a short period of time in use, the colours of the display change. In between these change periods, the display looks just fine. Sometimes I think the changes are also caused when I type on the keyboard.
So - colours change, sometimes you can still read some parts of the screen but the problem expands until the whole screen is white.

When I move the display to another position, the display is fine again but a few seconds later, the change in colours happens again.

An external monitor works just fine.


What can I do?
Should I trythe same things?

I have a problem to understand the vocabulary "bezel" - even with the help of a dictionary I didnt find out if you mean the whole display with the "LCD-bezel" or just the case in which the LCD-display is located in.


I would appreciate any help and say thanks in advance.

Florian

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#8 Post by RealBlackStuff » Sat Jun 07, 2008 6:47 am

Hi Florian, and welcome to our forum.
The bezel is the surrounding plastic (Fassung , Frontblende) that sits around the screen, and has 3 screws at the bottom to attach it to the lid.
You have to remove the screw covers first, take the screws out, then remove the outer 2 screw covers on each side of the screen, and take the 4 screws out. Check that the cable is properly inserted into the back of the LCD panel. Use some good tape to fix it in place if it is/was loose.
Check the LCD cable connector under the keyboard, and check the inverter as well.
Do all of the previously mentioned tests.
Let us know what you find.
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flo2323
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#9 Post by flo2323 » Mon Sep 22, 2008 5:05 am

Thanks a lot again for your help.

The problem could be solved extremely easily. Two screws on the right side of the display were loose. After correcting that, the display worked fine again, I didnt even have to check the LCD-cable.

Did I already mention that I love my T21? I bought it used over 4 years ago and used it daily and it still completes my tasks perfectly.

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#10 Post by madkat » Mon Sep 22, 2008 8:04 am

if tightening the screws fixed the problem - it only means that the real cause in the display connection cables, and the "adjusting" of the hinge moved them a little bit, just enough to work
ex: T30, TR451, TR453, R51, R52, X40, X60, R61, T400
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