A31: problem with LCD display

[crg7]

Hello:

LCD no longer displays image. It comes on for a couple of seconds and then goes off. I can see the image by shining a light on the screen. By changing the display mode (Ctrl, F7), the display comes on briefly and then goes off.
External display works fine.

Differs from other posters in that the display comes on briefly before disappearing.

Any suggestions?

Best
Reddy

[Robbyrobot]

Sounds like a flaky inverter to me. A bad backlight (CCFL) generally announces itself with a reddish or pinkish tinge in the display.

[ajkula66]

Your choices, by cost (small to bigger)

a) inverter. cheap to buy and test out.

if not, then:

b) backlight. not an easy job to replace.

if not, then:

c) motherboard.

Good luck.

[crg7]

ajkula66:

Why does my problem indicate a problem with the motherboard? Where does the signal to the laptop's lcd screen split from the signal to the external monitor?

Best
Reddy

[ajkula66]

To quote someone smarter and far more experienced than myself...

rkawakami wrote:

My understanding is that the LCD panel is driven digitally, whereas the VGA port is analog. Yes, there can be a digital-to-analog converter to provide for the external video signal. However, the S3 graphics chip in my T23 can drive the LCD and external monitor with separate images (desktops). I'm assuming that the ATI Mobility Radeon 7500 in the T30 can do the same. I haven't been able to find a datasheet on the 7500 GPU and verify that the output signals are on separate paths but this page at ATI's new home (amd.com) suggests it can:

http://ati.amd.com/products/comparisons ... rison.html

If the problem is with a bad connection or defective component in the interface between the graphics chip and the input to the LCD, that could cause a loss of video to the panel but allow the VGA port to operate correctly.

The GPU in question is the same one as on A31.

[crg7]

Thanks---that helps.