T43 LCD help

[mjm4jc]

I have a T43 that has no display, but I can see the faint icons on my desktop. It boots up perfectly, and this has been one of the best T43's up to now. I have fixed LCD problems in the past, but this situation stumps me a bit. I took a perfectly working LCD off my other T43 and hooked it up to this T43 with no change in display. I was thinking that it rules out anything to do with the LCD or even the ribbon/cable going to the motherboard, since each LCD has its own cable.

However, when I hook up my T43 to another monitor, it works perfect. That is why I'm stumped. Any ideas?

Thanks

[ajkula66]

Welcome to the forum!

Sounds to me like you have a blown fuse on the board, one of those that control the output to the LCD.

The reason why you have no problems with the external monitor is that there are two separate outputs for the VGA and LCD, and one can work perfectly well while the other one is shot.

More info on fuse locations and related stuff here:

http://nickpaton.fireflyinternet.co.uk/ ... 0links.pdf

[mjm4jc]

Thanks for the warm welcome. Yeah, I saw that diagram before but always thought that the odds of a blown fuse were pretty slim. Perhaps I better think again

One more piece of info: Just the other day, I moved the screen back and forth and then pressed FN & F3, and the screen came on. When I restarted it, it was black again. Haven't been able to get the display alive since. Do you still think it's the fuse? I guess the solder joint of the fuse could be loose and the opening and closing of the screen just shifted things around a bit to make it come on????

[ajkula66]

You might have a dirty or defective connector on the motherboard itself. If the fuse is indeed blown, Fn+F3 will do nothing.

What's the 7-character model number of that T43?

[mjm4jc]

26686GU

[mjm4jc]

ajkula66 are you there?? Where can I purchase these fuses?

[ajkula66]

Before you purchase anything, make sure it indeed is a blown fuse.

I believe that www.mouser.com would be the place to look for them...

Good luck.

[mjm4jc]

I guess I could take the MB out and try to re-solder the joints that hold the connector in place. What do you think?

[ajkula66]

I wouldn't advise that course of action...

[mjm4jc]

Not sure why?? I have fixed dozens of ipods/computers by re-soldering loose joints. It's easy with the right iron.

[ajkula66]

I'd try pinpointing the exact issue at hand prior to grabbing a soldering iron, but that's me...

[mjm4jc]

Thanks. I just noticed that you live about 30 minutes from me. I'm about 12 minutes from Jim Thorpe. Small world!

[ajkula66]

If you don't get the issue resolved within the next week, you may just wanna stop for a cup of coffee and let me take a peak at it...

[mjm4jc]

Wow, thanks for the offer. I will keep that in mind as well as keep you posted on any fixes/challenges.

thanks

[mjm4jc]

Started messing with the T43 again. Surprisingly today, when it was booting up, I pressed the LCD on/off switch up and about 5 times, and the screen came on as normal. I'm thinking that this rules out a blown fuse. LCD on/off switch bad/loose????? I really hate to have to get rid of this T43, since everything else works so good. Thanks everyone for reading

[BillP]

Started messing with the T43 again. Surprisingly today, when it was booting up, I pressed the LCD on/off switch up and about 5 times, and the screen came on as normal. I'm thinking that this rules out a blown fuse. LCD on/off switch bad/loose????? I really hate to have to get rid of this T43, since everything else works so good. Thanks everyone for reading

Maybe. I had that switch fall off the LCD cable on my T43. Try resoldering the switch to the cable and see if it helps.

[mjm4jc]

Oh, I thought the switch is soldered to the board, not the cable. Not sure what you mean?

[mjm4jc]

ajkula66, and suggestions???????

[ajkula66]

ajkula66, and suggestions???????

Apologies, neighbour, some of us have to work for a living, and my daily commute is 5 hrs +...

Anyway...remove the upper keyboard bezel, and use the machine without closing the lid for a couple of days, see where that gets you. No movement is preferred, the laptop needs to be on a stable surface.

[mjm4jc]

ok, I'll give that a try.

[AGoodSolution]

Started messing with the T43 again. Surprisingly today, when it was booting up, I pressed the LCD on/off switch up and about 5 times, and the screen came on as normal. I'm thinking that this rules out a blown fuse. LCD on/off switch bad/loose????? I really hate to have to get rid of this T43, since everything else works so good. Thanks everyone for reading

That isn't the cable.
It is tempting to believe it's the cable but what's happening is clicking the switch as if your closing the lid is sending a surge to the CCFL and momentarily reinvigorating a dying LCD the way a defibrillator can animate a corpse.

Flicking that switch, everytime I see this issue it is more often a dying/dead CCFL and sometimes a bad inverter.

I feel bad for anyone who logically attempts to implement sound troubleshooting techniques by replacing the SXGA / XGA cables since (it is fair to assume the LCD cable switch is bad) those cables rarely fail and they're a PAIN TO REPLACE.

Just to realize it was something else and the time +frustration disassembling a ThinkPad ingot LCD makes me regret dropping out of law school.

[RealBlackStuff]

If you are REALLY patient and handy, you can try and replace the CCFL yourself.
I have repaired many 15" screens successfully, but have only managed to finish one 14.1" screen (like yours is).
Every single one of them is a pain in the butt, the absolute worst is Hitachi, then Samsung, then LG-Philips.
You can find parts and instructions on www.lcdparts.net or they do it for you for ca. $75.-

[mjm4jc]

Yeah but keep in mind that I took the entire LCD of my other working T43 and put it on this one, and there was no change.

[ajkula66]

That very well may be a sticky switch.

Had an A31 once that I almost threw against the wall after I changed everything and it turned out to be a faulty switch...

[mjm4jc]

Well, the switch goes up and down really nice and does come all the way up to send the signal to turn on the backlight. Of course, this doesn't mean that the switch isn't still bad. I tired using it with the upper bezel off-----no difference. Have you ever changed the switch before?

[mjm4jc]

Greetings everyone,

I would like to bring back this thread since I never fixed the problem and would like to give this laptop away to someone for Christmas. Other than swapping out a working screen/backlight/inverter as mentioned in my initial post, I also swapped out the display on/off switch. No changes.

One other important piece of information is that if I take the end of my pencil and toggle the display switch up and down, I get a full bright screen every time I let up on the switch, but only for a split second each time.

Thanks,

Mike

[RealBlackStuff]

If you put the complete lid (which includes the LCD-cable with on/off backlight switch) on another machine, does it work OK there?
Did you ever check the fuses?
Have you tried another LCD cable?
The 1-second blasts if you push the switch could also point either to a bad CCFL or a bad inverter.

[mjm4jc]

No I did not. I have a spare T42 that works good. I can start swapping parts. Thanks