Powering off very shortly after power on - no boot, no POST

bvisness

Reputable
Dec 18, 2015
1
0
4,510
Our desktop (built by iBuyPower a few years ago) recently started failing to boot. It powers down shortly after you try to power it on, sometimes less than a second, sometimes up to 15 or so. No video signal to the monitor, even to show the BIOS screen.

I have followed your "can't boot" troubleshooting guide as best as I can, no luck. I have tried booting with just the motherboard, cpu, hard drive, and graphics card, no luck. I have tried booting with just the motherboard and cpu, no luck.

I thought at first that it was a PSU problem, since the lights on my cooling unit get rather dim when the computer starts. But I just went out and bought a new Corsair 750W PSU and the problem is still there. It looks to me like something is drawing a lot of current, but I don't know for sure.

I've inspected the computer for any shorts and can't find anything that would be a problem. And the computer did randomly boot once with everything plugged in, so it seems like each of the individual components must still be pretty much OK. When this happened, the cooling unit lights went back to full brightness before the BIOS screen appeared, and stayed bright.

Any ideas? I don't want it to be the motherboard...but does it sound like a motherboard problem to you guys?