Screen black (backlight on) external monitor working

Hi guys,

basically the title says it all:

I have a iMac G5 20" (2Ghz, 500GB, 512MB) which is working fine except for the screen being black. I know the backlight is working (and responding to dimming), so according to the apple guide (http://support.apple.com/kb/TS2094) it should be the LCD, but even with a replacement screen the display remains black.

What I've done so far:

- attached external screen - working

- tried another internal screen

- replaced display connecor cable

- checked capacitors - looking ok

I've run out of options to eliminate...

Anyone got an idea?

The screen's Model ist LM201W01 A5 K3, the replacement screen was the same. It might have been K2, but the behaviour was 100% the same: LED3 on, backlight on, pixels black.

The LVDS socket looks normal, all pins visible and undamaged.