My monitor goes blank randomly

[fourwood]

I think this is a hardware problem, as it happens in multiple OSs and even during bootup occasionally, but where it's definitely most apparent is in Linux.

The problem as it relates to Linux is this: after running Linux for somewhere around 5-15 minutes, my LCD will just lose the video signal from the computer. The system is perfectly normal otherwise. I can SSH into the box and even connect to my desktop through a VNC session, and everything works as it should. I can't get the monitor to come back without a reboot. This is true for both Gentoo, SuSE 9.1, and Knoppix 3.4. Knoppix seems to be the quickest at losing it, though.

In Windows it has behaved a little differently. Occasionally when I click my name on the Welcome screen, about 5 seconds afterwards the monitor goes blank. Though this doesn't happen very often, once I actually get the desktop fully loaded, it has no problems.

Then finally, very rarely, it will cut out even before it gets to a boot loader.

It seems a little odd that it happens much more oten in Linux than it does in Windows, but since the problem spans multiple OS installs, it leads me to believe that it's some hardware problem. Is the video card just dying? It's definitely not showing signs of overheating, as the display never gets corrupted, it just goes blank. Someone suggested that maybe it's a power problem, but I have a very new (3-4 months old) Antec Truepower 450W PSU, so unless it's faulty I don't think it would be the problem. So.. any ideas on what to look for would be great.

[Malus]

Maybe it is the monitor, not your video card.

------------------
[This message has been edited. Deal with it.]

[Emon]

Hmm, try swapping video cards if you have a spare, though I'm sure you thought of that already.

Perhaps the backlight in the LCD is dying? If it's a cold cathode backlight, it could easily be just crapping out from usage over time. Can you tell if there's no video signal or if the screen is just blank? Like on most CRTs for example, if there is actually no signal, the tube shuts down partially and it'll change power light color or whine that it has no signal. Do you get that, or does it just go black with no other warning? Try disconnecting the monitor cable and see if it yields the same or different result.

Speaking of cables, maybe that's it? Backlight seems the most likely to me, if it is a monitor issue anyway. When you reboot, the signal cuts out and comes back in, so maybe the LCD's circuits are putting more juice into the backlight to "start it up"..you know, like a fluorescant light needs sometimes. Although those are cold cathodes, they shouldn't suffer from such flickering issues. But you never know.

Best way to see if it's the backlight is to take a really bright light (well, at least sort of bright) and shine it on the screen and see if you can see anything. Move it around a bit, just to make sure you aren't drowning out any of the image with glare.

------------------
Bassoon, n. A brazen instrument into which a fool blows out his brains.

[fourwood]

<font face="Verdana, Arial" size="2">Originally posted by Emon:
Hmm, try swapping video cards if you have a spare, though I'm sure you thought of that already.</font>

Yeah. I'm sure I have a spare GeForce 1 around here somewhere, but I can't seem to find it. I'll have to look a bit harder later.

<font face="Verdana, Arial" size="2">Originally posted by Emon:
Can you tell if there's no video signal or if the screen is just blank?</font>

Yeah, the little power light goes orange, but the screen shows a message saying it has no signal from the computer.

I've tried unplugging the cable and reconnecting it to the DVI but it doesn't seem to change anything. That still doesn't rule out the possibility that maybe the cable is shoddy, but it's at least securely attached.

Well, time to go dig more for that card.

Edit: The exact message is "No signal. Going to sleep."

I found my GeForce, so I'm running Gentoo with that now. Will report back.

[This message has been edited by fourwood (edited July 16, 2004).]

[fourwood]

Lovely. So, the old video card works fine. Then, after putting my regular one back in, it seems to work fine as well. So, I guess the reseating maybe did it. Which is funny, because I reseated it just a couple days ago. Maybe when I reseated it I actually..... un... seated it. Bleh.. well. Seems I'm ok now. Phew. I really didn't want to buy a new video card yet.