T42 lcd screen dead?

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tensai_jin · #1 Post by **tensai_jin** » Sun Apr 29, 2007 12:54 pm

Hi,

I have had my T42 for a while now. Recently, my LCD just started to fail me. By failing, I mean that I would be doing my work, or playing some games when the screen suddenly turns VERY dark. If I stare at the screen under bright light, I can actually see the images, which means that the monitor is NOT off. Also, right now, I have connected an external LCD monitor to my computer and there is an image, which leads me to believe it might be my LCD that's at fault, not a software problem.

Can anyone tell me what's wrong? Or even better, a solution? It started because I have recently been plugging it to a projector on and off, which I thought might have been the problem.

I have tried playing around with power options, graphics management, but to no avail. When the screen dies, I can get it to brighten again by using Fn+F3 to turn off monitor, then pressing Fn to turn it on again. However, this is a temporary solution, as the screen becomes dark again after about 3 minutes. Any help would be greatly appreciated! Thanks!

#2 Post by **rkawakami** » Sun Apr 29, 2007 2:12 pm

The problem sounds like a bad inverter card. Fairly easily found on eBay ($10-$20), the FRU is 26P8464 for any 14.1" LCD, 91P7422 for the 15" XGA, 93P4161 for the 15" SXGA+ and UXGA IPS screens. All of this info can be found in the Hardware Maintenance Manual:

http://www-307.ibm.com/pc/support/site. ... 46464.html

There is a smaller chance that it could be the backlight inside the LCD panel or a problem somewhere on the motherboard. As the cost of the inverter is cheap enough, I would start there.

tensai_jin · #3 Post by **tensai_jin** » Tue May 01, 2007 1:36 pm

Thank you so much! I will try the inverter. Incidentally, does a bad inverter card start off with the LCD screen showing a red tinge? IBM replaced my system with another one a few months ago when they decided my fan could not be repaired for some reason.

The replaced system came with a red tinge on the screen at the lower left corner, which would fade away as the system heated up, so I figured I could live with it. Does this imply a bad inverter too?

#4 Post by **richk** » Tue May 01, 2007 1:39 pm

Red tinge usually means bad backlight.

Chris001 · #5 Post by **Chris001** » Wed May 02, 2007 7:59 am

tensai_jin wrote:The replaced system came with a red tinge on the screen at the lower left corner, which would fade away as the system heated up, so I figured I could live with it. Does this imply a bad inverter too?

Red tint on the LCD at boot = need replacement LCD panel or, if you are really handy at fixing things, a replacement backlight tube.

dcouzin · #6 Post by **dcouzin** » Wed May 02, 2007 9:32 am

My T42 screen has just begun to start with the pink color. Warranty expires in November. Good timing?

gunston · #7 Post by **gunston** » Wed May 02, 2007 5:22 pm

hmm.
my T43 lcd too, during the splash screen of the very first bios display. there is a big portion of flickering along the horizontal part of the screen, but it work fine under the windows.
does it relevant to the bad inverter card too????

#8 Post by **richk** » Thu May 03, 2007 11:00 am

Flickering at startup could be bulb or inverter, but it may also last a long time like that, so I wouldn't rush out and do anything.

Mahatma · #9 Post by **Mahatma** » Sun May 27, 2007 2:49 am

Thanks to this forum, I was able to figure out that my T42's SCREEN was dead. Among other things:

- the screen works with an orange glow that brightens as the machine stays on; but winks to black suddenly

- the problem does not go away when I use Knoppix (a CD method of booting to Linux)

- when the screen is black, I can see under bright light that it actually is working (the proper shapes and images are all there, just not back-lit)

SO NOW the question is where to get a replacement LCD. A fellow on eBay sold me a screen for $160, which was a bargain, except it wasn't (WRONG screen).

BOTTOM LINE

Does anyone have any suggestions about where I might buy:

- a bargain new screen?

- a refurbished screen?

- a used screen?

Many thanks!!

- Charles

New York, New York
Tilyou1@verizon.net
(212) 208-4446

#10 Post by **rkawakami** » Sun May 27, 2007 3:34 am

A belated Welcome to thinkpads.com! (lurked for awhile, huh?

)

As there are several possible LCDs used in the T42, you will need to be sure that you have the correct part number (FRU). Refer to the second post in this thread for more information.

Besides eBay, you can try here in the Marketplace, or the advertiser you see at the top of the page (The Laptop Guy). Your problem sounds like the typical broken backlight, however there is still a chance that the inverter is bad and/or the ribbon cable is defective. Unfortunately I know of no easy way of testing the inverter to see if it's actually putting out the correct voltage for the backlight. My suggestion has always been to carefully inspect the ribbon cable for damage. If that looks good, then buy an inverter (they're fairly cheap considering the cost of an LCD) and see if that fixes the problem. If not, then consider replacing the LCD. A backlight removal and install is possible, but it's fairly complicated work.

Mahatma · #11 Post by **Mahatma** » Sun May 27, 2007 4:56 pm

-- As there are several possible LCDs used in the T42, you will
-- need to be sure that you have the correct part number (FRU)

Pretty sure I have that from the IBM authorized place that tried unsuccessfully to install the screen I gave them, then figured out why.

-- Your problem sounds like the typical broken backlight, however
-- there is still a chance that the inverter is bad and/or the ribbon
-- cable is defective

The IBM authorized place was also sure it was the backlight -- not inverter or cable. One clue is that in bright sunlight, the screen can be seen to be working -- except for the fact it's totally dark.

-- you can try here in the Marketplace

Thanks for the tip!

-- Unfortunately I know of no easy way of testing the inverter to
-- see if it's actually putting out the correct voltage for the backlight

Easy, if you have a spare screen around (the IBM authorized place did, and it worked fine)

I find very irksome -- even if not new news -- that a refurbished T42 is available for around $900 (ballpark), but replacing THE SCREEN ALONE on an OLD machine is around $450. CRICKY the screen is worth more than the motherboard! which makes little sense. To use the machine temporarily I got a huge and very pretty (albeit AC powered) Samsung screen that has even higher resolution, so why is the freaking IBM screen, or really just the light bulb, such a big deal? All that's dead is the light bulb, it souldn't cost half the price of the machine to replace.

grumble grumple

I've had this problem in the past, but at least then I could blame myself (for shattering the screen by dropping it)

Charles

#12 Post by **rkawakami** » Sun May 27, 2007 6:23 pm

Actually, the CCFL (cold cathode fluorescent lamp; aka, backlight) costs only about $15. Replacing the lamp does take some fine handwork. If you are resigned to the fact that disassembly of the LCD panel to get at the backlight could destroy it further (requiring the purchase of another panel anyway), then you basically have nothing to lose in trying it. I myself have not yet performed a backlight replacement. I have bought a broken panel just to get some experience taking one apart. There is a sticky thread here that details the operation on a 600-series panel.

LCD panels have always been very expensive on the replacement market; it's one of those things about supply and demand I suppose. Yes, it does help to have a source of known good parts and be able to swap them around to prove something works or doesn't. Swapping in a complete lid assembly "slays three avians with a single mineral orb" (LCD panel, backlight, ribbon cable).

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