IBM T42 screen goes blank after every few secs after i press the sensor button

Hey,

A few days ago my Thinkpad T42 just went berserk on me. I turn on the
computer, everything is fine except the screen. It is on (displays) for
a few seconds then it turns almost completely blank like it shut down
(but I can see that it is not completely off, the screen is almost
pitch black, but if i stare at it i can see my desktop or whatever the
computer is up to very vaguely).

Then I press on the sensor button (same as closing the laptop lid) and
I can see now that it is completely black like it would be if it was
totally off, i release the button, the screen comes back on for a few
seconds, then goes back to the 90% black screen (and i can't use my
computer because i can't see what i'm doing).

What do you think is wrong? what can i do to fix this? please help.

-Kuang

 

Maybe I am wrong, but I think your backlight has gone bad. You
probably need to replace the backlight.

 

what's a backlight? is it a light that powers the lcd? how much do you
think it would be to replace it?

 

The backlight is a fluorescent lamp that shines through the LCD so that
you can see it. It is behind the LCD. It is not part of the LCD.

http://en.wikipedia.org/wiki/Backlight

 

I had exactly the same problem on my T40. I mistakenly thought it was
connected to the issue with the overcharged battery and capacitor,
since I also had that same problem at the same time. Nope. Sorry. Then
I noticed that there were security updates (including the infamous one
that fails when you have anything HP) that were installed right at the
time the problem started. I rolled back to a previous date. It worked
all evening. I thought I'd fixed it. Until the next day - aargh.

I then thought it was the switch on the "screen closed" interface,
because I could get it to come back up temporarily if I messed with
that button, so I replaced the cable assembly. Nada. Finally, I asked
some other people for advice. They said 9 times out of 10 it's the
inverter card. I got one (less than 20 bucks on ebay, including
shipping), and installed it - it's a really simple job, much easier
than the cable assembly. Before I changed this out, on the few
occasions that I actually had a screen, I could make it fail by simply
touching, bumping, or jostling the laptop (typing, or doing nothing,
actually). Now I can't make it fail even when I move it a lot, so I
think that was the problem. Of course, it's hard to prove a negative,
so just because it's working great now doesn't mean it will continue
to, but since it was so touchy before, I think it's going to be ok.

To verify that it's something this simple, and not your system board or
your video chip, plug in an external monitor. If you see everything
you're supposed to see, obviously your system board and video are doing
what they're supposed to do. It's just not getting onto the display.

Diane

 

Hi,

I had the same problem and found a solution. It seems the dvd rom is not screwed into the laptop, only plugged in. Moving the monitor stresses the point in the laptop where the cd-rom is, causing it to loosen. Then it causes the screen to keep going blank. The solution for me was to pull out the cd-rom. There is a little eject slider next to the cd-rom. First open the cd-rom. Then slide the slider. Then you can simply pull out the cd-rom. Then restart the pc. That fixed it for me. Right now, I'm trying to disable the cd-rom and leave it in. But disabling from device manager did not fix it. God bless you.

In King Jesus,
Joseph