T43 backlit/inverter/? problem

[thrackan]

Hi,
My 1872-4AG gives those symptoms:
- for the last two months the left lower corner of the screen was quite hot and tinted red immediately after lifting up the lid, but after few seconds it went back to normal, clear view and got colder.
- three days ago when I pulled out the plug from the wall the screen went very dimm, but still a bit visible with a help of the flashlight. After pluging in it into the outside source of energy it went back to normal.
- yesterday the screen lost his backlit every 5 or 10 minutes, and only way to get it back was to press the lid closing button near the escape button area. The inverter area also heated up quite strongly.
- now the screen is completely black (not even a dimm view) and pressing the lid closing button gives this short effect:
http://www.youtube.com/watch?v=bWAdQt6B4hw (forgive me the quality, a built-in camera phone is my only available filming device at the moment). It stays on longer and even reaches a clear, not tinted state for a moment, after loger shut down period.

I would like to ask you for help in diagnosing the problem. What can I do to fix it in the reasonable price range? Buy new inverter and replace it? Or maybe another part?

My Thinkpad serves me well, and I want to cure his disease

Forgive me my english, please. It became very rusty since I stopped using it to express my thoughts.

[Harryc]

It's most likely not the inverter. A red tint is a dead give-away to the fact that the laptop needs a new back-light. The easiest way to accomplish that repair is to find an entire LCD assembly for a T43, second best option is just to replace the LCD panel paying close attention to part number compatibility, the third option is to replace just the back-light. This last option very rarely results in satisfactory results due to dust and dirt getting into the LCD. Also going from a dim image to no image is troubling. You may have also blown a fuse on the system-board. Check that when you replace the LCD.

[thrackan]

Thank you for the reply.

Considering, what you have written, I'm going for the first option then - replacing the entire 14,1" LCD assembly. Is it important to buy exactly the same, or can I buy one with higher resolution? I have now Intel 900 graphics and 1024x768 LCD. Can I get one with 1400x1050? Or do I have to buy another one with exactly the same FRU parts numbers?

[RealBlackStuff]

Having a 14" machine with Intel graphics, you can ONLY use XGA (1024x768) screens. SXGA+ will NOT work.
The whole lid can come from any other 14" T40/T41/T42/T43. You just swap the clearplate if needed (small strip with T4x model and control lights at right bottom of lid).
Replacing just the LCD, it can come from the above T4x, plus any 14" R50/R51/R52.

[thrackan]

Thanks!

So I can choose any LCD from this link http://support.lenovo.com/en_US/product ... D=PD008744 , section 7, part " LCD panel XGA"? Manufacturer does not matter? (I have a Samsung FRU:92P6759 one on board). I know, that I'm asking many questions, but i want to avoid any possible mistakes...

You may have also blown a fuse on the system-board. Check that when you replace the LCD.

Just in case, how difficult is to fix that? Requires serious, tiny piece soldering?

[Harryc]

Just in case, how difficult is to fix that? Requires serious, tiny piece soldering?

The fuses are tiny, but you can solder a good one directly over a bad one (piggyback). The real challenge is going to be to find a fuse.

[thrackan]

Thanks!

I hope to find a tutorial or a service manual helpful in locating the fuse if necessary. But for now, I have found another syptom - there is a squealing sound coming from the inverter area during the time when LCD miracously manage to work properly (about a minute after leaving it turned off for few hours). Writing about it just in case it was important.

[ajkula66]

You should just keep the machine off for now...

[thrackan]

That would be quite difficult. This Thinkpad is the only computer in my house, and I have few projects I have to finish soon. Its LCD turns on automatically when I turn the T43 on, despite the fact that now Sharp TV connected by D-SUB acts as a main screen. I am not trying to use built-in Thinkpad screen now.

[ajkula66]

I would suggest that you physically disconnect the internal LCD and run it on external monitor only for the time being...

[thrackan]

I will try. I am going to buy as a screen source a T42 with broken mainboard (seller said it is famous GPU soldering problem). This is a photo from the auction http://www.radzrok.home.pl/ALIEN/IB2.jpg . It is 2374 type. Seller told me, that the GPU is one of the Radeon family and the LCDs maximum resolution is 1024x768. If there is something more that is worth checking (and possible through the phone to accomplish), I would be grateful, if you could tell me about it. Words like "it's okay, you can buy it" would also be appreciated. Thanks!

Edit:
Big thanks again! T43 has his own working screen again functional. Mobility is back