Ongoing T20 LCD issue

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Rex · #1 Post by **Rex** » Tue Sep 12, 2006 4:20 pm

Hi there,

An on-going LCD issue! Either the back light does not come on at booting (but it can be enticed to do so) or it all works and after about one hour, the back light switches off. Or that is what seems to happen. Some more enticing and it comes back to life.

Have replaced the screen cable and inverter, but the problem persists.

What to do? Any advice would be gratefully appreciated.

Next question; should I replace the back light or the whole screen?

The current screen is a Samsung LTN141x8-L00 (FRU 05K9678) See many screens on E-Bay but don't know if I can replace with a Hitachi or other make? Or even a T20 screen that has a different but similar FRU, such as 05K9677. Basically what I'm asking is, will any XGA (or SXGA) 14.1" screen work?

Again, grateful for any advice,

Many thanks,

Rex

Berny · #2 Post by **Berny** » Tue Sep 12, 2006 4:54 pm

replacing the back light only is almost ipossible on T2x. some people say its harder than brain surgery...

from what I know all 14" xga screens from all T2x are inter-changable.

keep in mind, that also your mobo might be the problem. i recommend to check the following:

1) connect to external monitor. enable both (internal and external) view. check when the internal TFT goes blank. does the external still show a picture? no picture on both --> mobo
2) when internal screen is blank, can you still see a very dark picture (have a close look from the side)? if yes --> back light problem

Rex · #3 Post by **Rex** » Tue Sep 12, 2006 5:04 pm

Berny,

Thanks for your reply.

Am pretty sure it is a backlight problem, as whatever the situation (booting or suddenly going off) there is a very, very faint 'ghost' image; so I guess the pixels are working.

Have not tried it with an external monitor to check if both go off because I feel it is the back light.

Actually, I think it is a connection problem, but don't know where.

Rex

#4 Post by **rkawakami** » Tue Sep 12, 2006 6:23 pm

Rex wrote:Actually, I think it is a connection problem, but don't know where.

One possible area to check is the lid closure switch. The backlight is directly controlled by this switch. Assuming you are running a version of Windows, then also check your Power Options Properties/Advanced tab and see what action has been defined for "When I close the lid of my portable computer". If it is set to "Do Nothing", then the lid switch will shut off the backlight AND not put the laptop into the standby or hibernate modes.

Rex · #5 Post by **Rex** » Wed Sep 13, 2006 1:43 am

Ray,

I will look at that. The switch is not sticking in any way but I don't know what the setting is.

But if set to 'Do Nothing', why would the backlight frequently not come on at booting and/or after about one hour, go off?

Have turned all the Power Management switchs to Never (always use the T20 on mains) but it is still flakey.

Guess I will solve it one day.

Rex

#6 Post by **rkawakami** » Wed Sep 13, 2006 8:35 am

Rex wrote:But if set to 'Do Nothing', why would the backlight frequently not come on at booting and/or after about one hour, go off?

My thought is that IF your power option setting is "Do nothing" for the action associated with the lid closure THEN a misbehaving switch COULD cause the failure of the backlight that you are seeing. This is assuming that when your backlight does go out, the system does NOT go into a standby or hibernation state.

Way earlier Rex wrote:Some more enticing and it comes back to life.

Can you be a little more specific what you are doing to cause the backlight to come back on?

tom_k · #7 Post by **tom_k** » Wed Sep 13, 2006 10:05 am

rkawakami wrote:Way earlier Rex wrote:
Some more enticing and it comes back to life.

Can you be a little more specific what you are doing to cause the backlight to come back on?

Maybe [Fn]+[F7] works in that situation,
My T23 sometimes cycles the [Fn]+[F7]-States by itself,
as if mentioned Keys would have been pressed.
This happens spontaneously, maybe 3 times/day or just 1 time/3 months, + no indication why.
The osd even shows the switching when it happens.
Never before heard about another T2 with that behaviour

tom_k
T23 98se.... 2x512MB 250Wh etc

awdark · #8 Post by **awdark** » Wed Sep 13, 2006 10:37 am

If you're curious about getting to the backlight....

http://img242.imageshack.us/img242/6540 ... 488rx8.jpg
Peel back the metal stuff from the side, don't cut it as you will probably hit some ribbons.

http://img242.imageshack.us/img242/8607 ... 494ce6.jpg
Assuming you had unscrewed the controller board, you can lift it a little.

You should be able to drop the lcd out and slide the backlight unit/light box out after you pop the frame off...

http://img242.imageshack.us/img242/9461 ... 497bm9.jpg

Unfortunately I didn't really pay attentin to the backlight as my LCD was damaged and my backlight was fine...

Rex · #9 Post by **Rex** » Wed Sep 13, 2006 5:02 pm

Gentlemen,

Many thanks for the replies.

Enticing the backlight means opening and closing the screen. After a few open/close (not totally closed) cycles, the backlight usually jumps back into action, usually when it is in the normal viewing position.

It certainly has the Fn+F7 appearance with a 'but' attached. The pixels do not switch off. The computer is still working and a very very faint image can be seen. Fn+F7 does not bring the screen back to life.

We use the computer mainly to watch DVD's and after about 45 mins to one hour, the backlight fails but can be enticed back again. I have had the computer running with the desktop open, and after about one hour, it is still fine.

I have replaced the LCD cable and inverter; I have checked and rechecked the LCD cables and sockets. Today, I semi-dismantled the LDC to see if I can get access to the backlight, but I feel that is a bit too difficult.

While the non-operating backlight frequently happens on booting, before totally reassembling and replacing all the screws, I reassembled everything loosely and could not make the fault happen. So I thought I had cured it. But when all the screws are replaced, it happens.

Starting to wonder if there is a short of some kind, but can't figure out where it could be. And if there is a short, it would not happen after one hour of DVD running.

I am happy to replace the screen but feel that the screen is not the problem so may be wasting money.

What to do next? This is the BIG question.

Rex

Berny · #10 Post by **Berny** » Wed Sep 13, 2006 5:59 pm

Rex: I don't want to be impolite, but why do you post your problem twice within 2 weeks?

http://forum.thinkpads.com/viewtopic.php?t=29698

why do you let us ask the same questions? why hadn't you just bumped your old thread?

a very strange way of asking for help...

Rex · #11 Post by **Rex** » Thu Sep 14, 2006 4:21 am

Berny,

You're right, and I should have 'bumped' the thread, but I don't know how to do that.

I hoped that by restarting the thread, I may find someone who doesn't usually read the forum, who had a similar experience. That doesn't seems to be the case, however, there have been really interesting answers that I have checked out. Unfortunately, I have not (yet) been able to resolve the problem.

May be reposting is not good etiquette, for which I apologise, but hey, it certainly isn't the end of the world either!

Rex

ninjapirate350 · #12 Post by **ninjapirate350** » Thu Oct 12, 2006 11:13 am

Rex, I have the same issue with my t20 right now.

I find that my computer only does this on boot-up after sitting for a while, but after I get the computer up and running and play with the LCD till it works it works fine. It never give me trouble again until I shut it off for a few hours or at night. I have not replaced anything yet but I have found that if I wiggle the monitor cable (I removed the little protector cover for this) I can get the backlight on again. It has to be a short somewhere. If I can't get it working again and end up having to replace the backlight I think I'll just scrap the laptop for parts on here or ebay or something.

Rex · #13 Post by **Rex** » Thu Oct 12, 2006 1:12 pm

Philip,

Thanks for the reply. As an up-date, it sure has me flummoxed!

I have a T22 also, so put the 'non-working' screen into it. Guess what, it worked, so I concluded the problem was with the T20 SystemBoard. Bought one off eBay (actually, it's a T21 systemboard) and took all the bit off my T20. Screen still not working. So bought a replacement screen off eBay and that does not work.

Now have almost enough parts to build a non-working ThinkPad!

System board, screen, LCD cable and inverter.

Will do a number of induvidual replacements with my working T22 and try to see which part is not working, but frankly, I think they all are!

Rex

ninjapirate350 · #14 Post by **ninjapirate350** » Thu Oct 12, 2006 4:16 pm

Good to hear you were able to figure out it what it was, I may try taking the multimeter to the monitor connector on my motherboard and see if I can figure anything out. Some connection has to be loose that's causing it to do this. Perhaps I may be able to fix it with the soldering iron.

Rex · #15 Post by **Rex** » Fri Oct 13, 2006 1:11 am

I think yo are correct in saying that a monitor connection is loose.

Last night, I put both the replacement screen and inverter into the working T22, and everything worked. Did not try the LCD cables as that involves rather a lot of dissassembley.

Figured that the problem is with the systemboard. Now I think the problem is with power getting to the inverter from the systemboard. But how to figure out what is what is another issue and frankly beyond me.

If you have any suggestion, I would be really grateful as I now have almost two of everything and could build two working Thinkpads if I knew what to fix.

Rex

ianf · #16 Post by **ianf** » Tue Oct 17, 2006 5:36 pm

hello rex
you must be down the road nearby ,
i have come to the same conclusion having replaced the backlight t23 , exteral 2nd display works fine ,pixels faintly showing , tried inverter in t22 thats fine , strangely if i pull the m/b display connector on and off rapidly the screen faintly lights not enough to display pixels correctly , so conclusion is no power to inverter or inverter has a short and the initial surge is sufficent to cause partial display hope some one can say which pins provide power plus the other functions at the inverter plug end.

ianf

Rex · #17 Post by **Rex** » Tue Oct 17, 2006 5:55 pm

Ian,

I haven't totally given up (yet) but did call the IBM helpdesk. They could not provide any information and when I asked if there was a circuit diagram available, was told, 'No Way Jose!'

They even said that the Helpdesk do not have that information. If the problem is on the circuit board, I reckon that it will be virtually impossible to repair. However, I am forever optimistic that the fault is nothing more than a connection.

Rex

Ongoing T20 LCD issue

Ongoing T20 LCD issue

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