Thinkpad R52: No Backlight - comes back only for some seconds when switching to external monitor

[joebee]

The LCD panel is dark. One can see that the display is still working - only no backlight.

When pushing the lid switch (which turns of the LCD when closing the lid) the dark screen turns to black. I.e. this switch is working properly.

External monitor is working.

When changing with "Fn/F7" between LCD panel and external monitor the backlight turns on for a few seconds but quickly turns dark again. In the moments when the backlight turns on one can see that the display colours and everything are quite fine... (so no redish which would indicate a lcd problem).  Moving the lid mechanically cannot bring the light back.

I was sure it would be a problem of the LCD flex cable and replaced it - but unfortunately with no result.

Would be glad about hints what could solve the problem!!!

Maybe changing the inverter?

Or might it just be a bad soldering joint or loose cable connection? But where? In the lid or on the main board...?

Changing the panel itself is of course a quite costly affair..

Thank you for your help!!!

(Model No.: 1858-3BG)

[ajkula66 Guru]

Chances are that the backlight itself has gone bad.

Has your screen been reddish/pinkish on cold boot prior to this last episode?

[joebee]

Prior to this problem the screen was quite normal - no reddish/pinkish.

And as the backlight sometimes comes back for a few seconds (mostly when switching to ext monitor) the general funktion is there. Only some loose contact or whatever..

But where and how to fix it...?

Thank you! Jochen

[lead_org Microsoft MVP Contributor]

sometimes the reddish problem doesn't come up before the CCFL failure occurs, but reddish/pinkish problem is a good indicator of imminent CCFL failure.

[MrPeter1985 Guru]

Have you tried the FN key to turn the screen brightness up?

[joebee]

Yes, I already tried this - but with no effect.

Now I ordered a new inverter. Let's see if this helps...

Thank You!

Jochen

[radim]

Hi Jochen, I'm having a similiar issue. Did replacing the inverter solve your problem?

Thank you!