T41 LCD Problem

[npolite]

Hello,

Recently I started having problems with my LCD screen's backlight going out but the display still showing if I put a flashlight to the screen. The display inverter board started making a hissing sound which from what I read online was a failing board. So I replaced it with a used one thinkpad-parts.com. What I found out from IBM was that the existing model number was replaced with a newer model number from a T42. I got the replacement part and everything was working ok two days ago. Then late last night it did it again, backlight went out. Again this morning the replaced inverter board started making the hissing sound. Checking these forums some have suggested that I replace the cable going from the inverter to the screen, is this what it sounds like? Also I was touching the area around where the leds are and it feels warm. I don't remember if this was the case with the old one.

The response I got from one of the salespeople at thinkpad-parts.com was

"likely the lcd panel or system board is the problem they think it may be burning out the sl inverters or causing them to malfunction"

Does this seem to be the case? Will this be a pricey repair if I have to start gutting parts out to figure what is wrong or is the inverter the problem?

Any help would be appreciated.

Nick

[Harryc]

I'd have to agree with the guys at thinkpad-parts. The CCFL (backlight) is shot and it is taking out inverters. There are many T4X parts out on EBay these days, I'd pick up an entire LCD assembly and replace the whole thing. Just make sure you get the right size and resolution. Any panel from a T40, T41, T42 or T43 will work.
As an example - http://cgi.ebay.com/LCD-Screen-Display- ... 0352422358

[npolite]

This sucks because if I buy a used one, it may only last a few months depending on how much use it had. And paying $260 for a new screen is not worth it. Oh well, time to recycle it or sell it for parts.

[rkawakami]

True, a used panel has no guarantee on the amount of life still left in it (and probably the same can be said for a new LCD; negating any warranty coverage that might be available). But a T23 SXGA+ panel that's been in my possession for over two years and shows the "pink hue at turn on", typical of a CCFL that's failing, has nevertheless continued to operate daily for me. It's probably doing that since it knows that I have a replacement lid ready to be slapped on whenever the backlight does eventually fail .

It would be a good idea to check the wires from the inverter to the backlight. If there's a nick in the insulation, that could cause a short which could be taking out the inverter. It's also possible that a loose connection to the backlight is blowing out the inverter. This could be anywhere from the inverter board's output jack, all of the way up to the ends of the backlight (which will be buried inside the panel).

ref: http://forum.thinkpads.com/viewtopic.ph ... 28#p494928
ref: http://forum.thinkpads.com/viewtopic.ph ... 03#p333603

[npolite]

Ok so I've disassembled the screen and got the CCFL bulb out. I'm going to order a new bulb and I guess form what I have found, will need to re-solder the wires onto the new one. Does anyone know of a reputable dealer in the US where I can order a new one from? Also now that the inverters have started to make a high pitched noise, are they shot because of the CCFL and I need to order a new one as well? Can I test the new bulb on an existing inverter without damaging the bulb just to make sure I have assembled everything correctly?

Thanks,
Nick

[Harryc]

http://www.lcdparts.net/howto/S_CCFL1.aspx

[npolite]

OK thanks for the link. I've ordered a new one. As for the inverters, they were hissing prior to the change, is it safe to reuse them or do I need to get a new one?

[Harryc]

I have heard of defective CCFL's taking out a known good inverter. If it were me and I was going to go through all that work to replace the CCFL, I'd also put a new inverter in there for good measure. They are relatively cheap.

[npolite]

Ok so I have replaced the CCFL. It took me a while since the terminals had to be snipped a bit from the vendor I purchased it from. I'm waiting on the (used) replacement inverter but have powered it up and it is working. My only problems I am seeing is that in the lower left hand corner and near the middle bottom of the screen the light is a bit brighter than the rest of the screen. Do I need to re-seat the CCFL again or is it the brightness of the CCFL that is causing this?

Thanks,
Nick

[richk]

It is really hard to get the bulb in right. Also, the all replacement bulbs I've tried are just a hair shorter than the original. That makes them easier to install, but they don't give as good of a result. I've about given up replacing bulbs, The economics are poor. They take a long time to do, and the finished product is seldom satisfactory. Replacement T4x screen assemblies in good shape only tend to sell for about $70.

[npolite]

It is really hard to get the bulb in right. Also, the all replacement bulbs I've tried are just a hair shorter than the original. That makes them easier to install, but they don't give as good of a result. I've about given up replacing bulbs, The economics are poor. They take a long time to do, and the finished product is seldom satisfactory. Replacement T4x screen assemblies in good shape only tend to sell for about $70.

Yep I was weighing that in but then the question of how long the used panel will last again. You may be at the same situation in less than a year. Any way you put it it sucks when these things go.

[npolite]

Well I got the backlight as good as I'm going to get it. This last try is almost perfect. It has been 3 days now of use and the screen is looking good. Thanks to everyone for their help. I got the motivation with the crappy LCD R500 that I ordered. This T41 will be my last Thinkpad, the new ones are no better than any other manufacture out there.