PSU problem or motherboard problem?

[lchyi]

Okay I've had this setup now for about two weeks and after RMAing a power supply I fear that the problem is my motherboard instead. When I hit the power button, the fans whir for a good second and then stop. I called three places and they all said it was the power supply. Then after I got my new one in the mail, it did the same thing. Now, throwing aside the two dead PSUs in a row, I think it's my motherboard now. When I take it out of the case to eliminate any shortage problems with the standoffs and whatnot, I plug only the basics in (proc, ram, a fan, hsf, 12v, and the big plug) and then touch the power switch things with my screw driver. Same thing. It starts for a second then stops. Now would this be a mobo problem or a psu problem? Or is it supposed to start and stop. I dunno.

 

[mechBgon]

If you try to start it again after the initial try, does it give it another half-hearted spin, or does it take a little "cooling-off period" before it'll try again? These power supplies you're using, are they a good brand or a so-so brand? What wattages?

It sounds like you're quite a ways into the troubleshooting process already, but if you haven't done this, do try resetting the CMOS while the system's unplugged, and look the mobo over closely to make sure that a screw hasn't lodged between some pins and caused a short or something. Good luck

 

[mechBgon]

Also, I guess I'm jumping to the conclusion that this is regarding the system in your signature. Is that correct? If it's an AMD system, make sure the heatsink is on the right way, because this would be a classic symptom of Reversed-Heatsink Syndrome on a Socket A board.