OT: No video signal from my PC. Any ideas?

NickHope wrote on 1/29/2009, 7:52 AM
My PC is based on an Asus P5W64 WS Professional motherboard and has 2 x Gigabyte Geforce 8600GT with 2 x DVI on each.

After being away for a while I recently turned on the computer and everything lights up on the main unit as it should, fans and hard drives whir, but I get no video signal whatsoever. Just black monitors. I've tried various monitors in each of the 4 DVI sockets but no joy.

This happened once before and that time I switched the graphics cards to different slots etc. but still no change. So I sent the PC up to the shop that built it in Bangkok and I basically got the message "Why have you sent us this computer? It's fine!" ... and it was.

Anybody got any advice before I box it up and send it off again?

System spec is in this thread.

Thanks!

Comments

Jay Gladwell wrote on 1/29/2009, 8:35 AM

Go ahead and box it up and make it think you're going to ship it off. Spend the next day moving the box around (as though it were being shipped).

On the third day, open the box and everything should fine, just like last time!

Seriously, I wouldn't know what to tell you, Nick. I wish you the best trying to figure things out on this one.

Computers are like women, you can't live with 'em, you can't live without 'em.


johnmeyer wrote on 1/29/2009, 8:50 AM
The one obvious thing is to pull the board out and then put it back in. Re-seating the board sometimes helps.

If the board design can be put in another chassis (another computer), you could try that.

Is there some sort of switch in the monitor, or somewhere on the board that determines which output is driven? Some boards have several outputs, sometimes analog and digital, and while they are supposed to auto-switch, perhaps there is something over-riding that sensing.

The fact that it works one place (their shop) and not another (your place), and it sounds like you are in Thailand, makes me wonder about your power levels. I have a good friend that does a lot of business in the far reaches of Thailand, and he tells me that voltage levels can vary a lot.

FilmingPhotoGuy wrote on 1/29/2009, 9:02 AM
If it's not a "discreet board" then it'll have an on-board graphics adapter. You should be able to disable it in the BIOS so that it reads PCIE slot first.

Just a thought.
NickHope wrote on 1/29/2009, 9:12 AM
Haha Jay, I might well try it. I pretty much know it's one of those indeterminable problems but I posted here just in case one of you bright bods analyzed it as self-inductance in the marmalade circuit requiring 3 tweaks of the purple nadger next to the fuel injector.

John, it may be power-related I suppose. The box is hanging off an APC 1000VA UPS but the monitors are either not on a UPS or on a Thai-made UPS.

I'll check out the power and then transfer the whole gubbins of the computer into my older Lian Lee box (which I prefer anyway), shuffle things around a bit, and see what happens.

Edit: LightAds, thanks for the suggestion but it doesn't have on-board graphics.
johnmeyer wrote on 1/29/2009, 9:45 AM
John, it may be power-related I suppose. The box is hanging off an APC 1000VA UPS but the monitors are either not on a UPS or on a Thai-made UPS.Possible ground loop. If you can temporarily put the monitor and computer onto the same power strip, try that. I have personally blown out a fax machine, an answering machine, and almost blew out an old CRT monitor from a really bad ground loop (caused by an electrician's mis-wiring of my house neutral wires). The wiring was according to code, but created a huge ground loop. Really strange, and ultimately really bad things can happen.

All equipment from a home theater, or in an editing office, should ALL be connected to the same circuit, preferably from the same power strip going to one plug in the wall, if your setup is small enough to allow that. If more than one plug must be used, make sure they are connected to the same breaker. If you have more power than can be taken from one circuit (e.g., more than 15A or 20A in the USA), then make sure -- and this is VERY important -- that all the plugs are on the same phase. Failure to do this can and almost certainly will result in all sorts of gremlins that come and go, depending on what loads are turned on elsewhere in the house or office.