is this an Inverter problem?

[mattatec]

My T42's screen is not lighting.
2373-JXU, 15" SXGA+.
I have previously replaced the screen (6 months ago) due to a backlight problem. but this is different. This time the screen is just completely black, can't see the desktop at all. There were no warning signs from the screen (flickering, dimming, pink hue etc.) however i did have a couple of wierd blue screen crashes the day before it died, which never happens on this laptop.
There is a barely perceptible change of light a few seconds after you power up which i assume is the windows screen loading, but there is nothing else to see, even in a dark room.
Working fine on an external monitor.
Could this be an inverter issue?

Thanks for any help,
Matt.

[sjthinkpader]

If you have two DIMM modules, try both one at a time first. It is unlikely LCD would cause a BSOD.

[mattatec]

tried removing the addon dimm (the other one is hidden). but it didn't fix the pronlem.

[ajkula66]

Has BSOD included an ATi-related message? If it has, your GPU is on its way out.

[mattatec]

can't remember if it did or not.
would it still work on an external monitor if it was a gpu problem? because it works fine this way.
are the gpu's replaceable?

[ajkula66]

GPU is soldered to the motherboard and hence not replaceable in its own right, you'd have to swap the whole planar, or repair it.

And yes, on quite a few occasions I've seen failing GPUs display on external monitors, but not on internal LCDs. This is due to different outputs-analog for VGA and digital for LCD.

Hope this helps.

[richk]

Going back to the first question, in most cases, a machine that works on external but not on LCD has a bad bulb or a bad inverter. Most bulb problems give a red tint before failing.

[mattatec]

thats what i thought, i'll try a new inverter first.
thanks.

[sjthinkpader]

Really never seen an inverter caused BSOD. If it is GPU the MB is toast. Try the other DIMM under the KB if you haven't already. Or remove everything except one DIMM and HDD then try booting.

[mattatec]

ive tried this, but no luck. i hope the bsod is unrelated. will try the inverter and see if that works first.
thanks.

[mattatec]

Have changed the inverter but it didn't fix my problem.
could this really be a graphics card issue?
any ideas on my next move?
thanks.

[rkawakami]

Loss of just the backlight illumination can be caused by:

- a bad lamp (CCFL) inside the LCD panel
- a bad inverter
- a bad ribbon cable
- a stuck or broken lid switch
- blown fuse on the motherboard (see: http://forum.thinkpads.com/viewtopic.php?f=2&t=72861 and http://forum.thinkpads.com/viewtopic.ph ... 78#p455878 F7 is reported to be the inverter fuse)
- or some other power/signal problem on the motherboard

Boot the system without an external monitor connected and if you shine a strong light onto the panel at an angle, do you see any video activity? If so, then you may not have a problem with a loose GPU.