Running Fedora 17 x64 with KDE. This is not new hardware and has worked fine in the past, but periodically the monitor shuts off during use. I mean the power light goes off, not even yellow. Tried other monitors, same result. Tried switching between a VGA cable and DVI cable, same result. Replaced the video card, same result.

The monitor may stay off for 5sec or 5hours no rhyme or reason. The computer still runs fine since its okay when the monitor comes back. I have noticed that when it gets turned off I can get it back by unplugging 120VAC and disconnecting the signal cable.

Any thoughts?

Um. Power management settings?

I suppose that is possible. I dual boot this machine with Win XP. This happens in either OS. So bios?

Is it by any chance plugged into an outlet on the computer?

I wouldn't think that a monitor would be powered off -- mine are on 24/7, they go into display off after a period of inactivity over a long time (like at night), but powered completely off? Nope, never seen that on any monitor anywhere.

And it isn't the monitor because you've switched it out with another, so that might leave the power supply, like a UPS or goofy power strip, maybe?

Tiz a puzzlement.

Finally resolved this matter.

Turns out the motherboard/video card combination damaged every monitor I plugged into it so that the problem seemed to infect other computers. The problem escalated until the monitor would stay off for hours at a time. Replacing the video card alone didn't fix the probem becuase the damaged monitor was still connected and eventually the new video card went bad also. This required a simultaneous replacement of the motherboard, video card and monitor.

Problem gone.