I didn't try these tips, but I will keep them on file for future reference. I ended up doing a clean install of the operating system and removing AfterDark. As far as I can tell the problem has been solved. The user is no longer experiencing crashes and error messages. The only thing he currently complains about is the loss of his screensaver.
At the risk of stating the obvious, you don't have the rear power button in the always on position, do you? There is a button with a little slot in the ps at the rear of the machine that could be set to be always on, presumably for servers.
Button at the lower left (on a Q650, but this is the same thing ps-wise):
I resurrect this old thread because I tested a bunch of black lcd with know good logic board and good inverter. Basically I simply swapped the black lcds to a known good combination of inverter and logic.
Lcd recapped but the black syndrome stays therefore it must be something else on the lcd circuitry.