PC problem with powering on

[Drifter]

I built a PC in January and immediately started having this problem where I would push the power button, but the lights and fans would only come on briefly (as if booting up) then they would go dead. However, sometimes it would power on just fine, and when it worked it stayed on until I turned it off. If it failed I would reset the PSU and try again until it worked. There was no pattern to success or failure.

The power supply was a junker that came with the case so I replaced it with an Antec TruePower 430w, but the problem persisted. I then took the PC apart to do a barebones boot. I discovered that the problem only occurred when the power is connected the video card, a PowerColor Radeon 9800. I tried the card in another pc and there were no discernible problems, which led me to believe the motherboard, a Soltek K8AN2E-GR, was at fault. I RMA'd it and received a replacement and the problem still perstists.


Any ideas?

 

[mailpup]

Just asking but is the 2X2 square, white power connector plugged into the motherboard?

 

[Drifter]

Yes, and I have disconnected/reseated power connections on both the old and the replacement motherboard. The only thing that I've done that has made a difference is unplugging the power to the graphics card.

 

[tdeg]

I hate to state that obvious, but... could it be your video card then?

It sounds like you have done all the PD for it.

I've had a video card hold my system down before.

 

[Drifter]

The only thing holding me back from that conclusion is that I put the card in another pc and it seemed to work fine.

 

[poertner_1274]

Have you checked the RAM? That can cause all sorts of problems.

BTW
:wave:Welcome to TechSpot:wave:

 

[zellyman]

Are you sure that the power source is adequate for the amount of power needed? It also sounds like heat could be the culprit, The more fans the better. Also make sure your motherboards thermal shutdown settings (If you have them) arent too low to compensate for the heat that the card puts off

 

[Drifter]

Thanks for the replies.

The ram seems to work fine. It shows up in POST and system manager. I've tried 1 stick, blown off contacts, reseated, and I've checked and rechecked my manuals and I can't find anything that would make them incompatible. As I've said the only thing that makes a difference is when I unplug the power from the video card.

The pc would run (still had the same problem though) on the clunker psu that came with the case and that was a 350w. I bumped it up to the Antec 430w which also has dual 12v rails.

When the problem occurs, the pc lights up/spins fans for less than a second so I wouldn't think heat is the problem. Also, when it actually came on, it never randomly shut off and I never saw any white artifacts when playing games or anything. Could "thermal shutdown settings" be the problem? I'm unfamiliar with them.

Edit: The temperature sensor in my case never registered more than 100 F and that was when it was 110 F outside. Before summer, it probably averaged between 78-82 F.

 

[zellyman]

The thermal shutdown is a feature on some motherboards that just halts the system when it reaches a certain temperature. That dosent sound like the problem though, considereing what your telling us