IBM T40 with display issues

[tweberis]

I have read the forums pretty thoroughly before joining for some tips but now I am seeking some help. I have this IBM T40 2373-PU7 and the display goes out after just a few minutes (max). The symptoms experienced pointed to a bad inverter but after replacing it I had the same issues.

It left me with two issues. The CCFL or the Mobo. I can still see a dim picture right when it goes out. I tried connecting it to an external monitor and using Fn+F7 to change the video output but it doesn't switch over.

Since it doesn't switch over, I presume it to be a mobo issue instead of the CCFL or inverter (or eventhe LCD Cable). Any suggestions on what I can look for on the mobo or where/what change on the mobo to help me out?

Or if nothing can be done, I will sell the thing as a whole or part it out.

[bontistic]

This is a little strange, you said initially there was a display on the LCD and goes out after a few minutes. This really could be an inverter problem. Since you can still see the dim display.

What I am surprised about is that the external monitor does not work. You can check one thing for now, make sure that the VGA cable is firmly connected to the motherboard and that it is working properly (possibly on another T4x or if the monitor detects the connection from the motherboard).

All of these are assuming that you have installed the correct P/N for the inverter board right?

[tweberis]

Thank I will recheck the cable to the motherboard and the inverter just to make sure its solid on both ends.

The new inverter is the same using the FRU number to replace it but it comes with a 120 day warranty so just in case its bad I still have a shot at another one.

Will post when i check the cable connections.

[tweberis]

*UPDATE*:

Couple of new things:

1) Every now and then, the backlight goes out and there is not set pattern. Sometimes its an hour later, sometimes not until after several reboots. I can still see an image faintly though. This is with the new inverter and rechecking the LCD cable to the motherboard and the inverter. When this happens I can hit Fn+F7 to change the video output and back again and the backlight then comes back on. Any ideas?

2.) More often that not the video goes out completely... not even dimly is it there! Fortunately I was able to get a remote desktop program on there and when it happened i VNC'd onto the laptop and caught a screen shot.
img]http://img524.imageshack.us/img524/423/ ... fo4.th.png[/img]

It's when this happens (presumably every time there is NO video not even dimly) that I have a hard time recovering from. I have to reboot several times and move the laptop around before I even see the boot logo. Any ideas?

*EDIT 2*
Okay here is the thing. I am pretty sure its not an inverter or backlight issue anymore. When the screen does come on. it doesn't crap out ever.

Now, whenever the screen does crap out on me, it goes completely black. It appears that the system crashes to because I cant access anything remotely like I used to be able to do.

The interesting part is, when this does go completely black, even when rebooting, I don't see any POST screen either. Just that the system acts like its fired up but doesn't do squat.

Is the video chip the cause of all this? There is one weird thing I have noticed. If I remove the battery and leave the laptop unplugged from at least an hour, when I plug it back in, I get the screen to display again but soon thereafter shuts off (crashing the system). If I leave it without a power source for a week I can get it to display for quite some time (was able to reinstall from preload, upgrade to SP2 and install all post-sp2 updates and some programs without issue) but that brings us to present where I can't get it to stay on any more.

I decided to check.. this laptop is still running the BIOS of 1.07 and latest is 3.21. The interesting thing is that its running the Embedded Controller program 3.04 and a later BIOS is required to work with this version. Could this be the root of ALL my problems?

[Harryc]

This sounds like a video chip problem to me. Pop open the keyboard and push down on the video chip to see if the display comes back. See the sticky at the top of this forum.

http://forum.thinkpads.com/viewtopic.php?t=33952

[tweberis]

Was on vacation for about two weeks so I'm just getting back home to work on it. Since I left the computer off for two weeks with no power source attached (see previous posts) I was able to run the laptop over night!!!!!!!! The first thing I did was update the BIOS so it and the EC program are running as they should. Unfortunately, this didn't change anything. After running it the problem started again, first the backlight would shut off and then the screen dies completely and the system crashes.

I read the forum link you posted and it sounds exactly like my problem. I know the backlight is good, and I already replaced the inverter so thats good. Looks like I'm left w/ it being the motherboard.

This only seems to happen after the system has been running a while like something is getting too hot. Perhaps I should try the long fan that covers the video chip as well?

I will try pressing on the video chip and seeing if that helps at all. I will also take the motherboard completely out and look at the under side for any "hot" or "loose" soldering points.

[kkartikeya]

Hi,

I am having same problem with my T40, talked to ThinkPad support, they are quoting max $575. This is too expensive for me.

Did you find any solution to your display issue?

Apprecaite your reply.

[tweberis]

I haven't had time to pull out the motherboard and look at the feet of the video chip. I am pretty sure thats where my problem lies, but will post more when I find out.