A7V600 > no video on VGA

[CyberDude]

When powering on the machine, everything seems to work normal (fans, dvd player, LED's)... except there's no video! That is, lots of time. Sometimes it does have video on the VGA, or it appears on the s-video output (tv).

I don't know what blocks the video. I tried 2 video cards: geforce 2, and now a brand new gigabyte 6600. Same thing. What I do notice, is that when it works, the mobo gives a beep right after powering up. And vice versa: no beep, no video.

There is also another issue, it may have to do with it: when connecting a second display (on the DVI), the system freezes. Tried forceware 78.xx and 84.21

ASUS A7V600
SATA 160 MB
E-MU 1212 soundcard
Gigabyte 6600 fanless 256 MB
Dell 151 (or something) LCD
Dell 2001 LCD
Panasonic AE900 beamer
windows XP sp2

 

[DonNagual]

Everytime you turn your computer on, it does a self test (Power On Self Test, or POST).

If you get a single beep, that means the system has passed the tests, and can power up. The times your system does not pass the tests, you are getting no beep, and thus no video. So the problem is not likely your video card, as if there is a problem with the video card (most boards anyways) you would get a different beep code.

No beep is usually a ram issue, but not always. Start by testing your ram. Download and run this program:

www.memtest.org

You unzip it onto a floppy, put it in the floppy drive then reboot your system. It loads up in dos. Let it run for 6 or 7 passes (will take a few hours).

Another posibility is a dying power supply, but let's test the ram first.

By the way, have you added any new hardware lately?

 

[CyberDude]

Thanks 4 the reply.

It is doing pass 7 of memtest86+ now. Zero errors.

By the way, have you added any new hardware lately?

I finished building this computer just a few weeks ago. (I bought everything 2 years ago, but never had time to make it work). All parts are brand new. It is meant as a HTPC.

The case+power is an Antec 2650 (350W). Temps (CPU + mobo) are fine (below 40C). Memory is 256 MB non-ECC.

The strange sometimes-no-video behavior always was there. When I take out and put in the video card, the problem goes away. Also when I touch the card (the silver plate) with a s-video cable, which has a fairly high voltage, usually helps. The computer is grounded.

When there is video, it usually keeps working for the consecutive sessions. The problem arises when trying to connect a second display, which I don't succeed in.

 

[DonNagual]

Hmmm. It almost sounds as if something is shorting out on your case or something. Have you tried removing your motherboard, and then reinstalling it while checking for any possible areas where your mobo may be touching the case?

Other than that, I suppose all you can do is troubleshoot one thing at a time. While you have your motherboard out, I'd sit it on a box beside your case and then remove EVERYTHING but the CPU/heatsink, one stick of ram, graphics card. Plug the PSU into the mobo, and connect the speaker wire from your case to the motherboard, then short the "power on" pins with a screwdriver.

Try going into your bios a few times, and see if you encounter your problem or not.

 

[CyberDude]

I followed your advice to the letter. Detached the mobo, only PSU, CPU+fan, VGA, case fan (it is attached to a molex). No luck.

When powering on, the fans are working. Also, there is some signal being sent to the monitor, because it says 'no signal' when powering the mobo

Also tried with the SATA hd; you can hear for a few seconds that it works.

Tried the old Geforce 2 card; tried the tv output via the s-video.

Checked a molex, it gives 5 V + 12 V.