Troubleshooting help: system went POP!

[LintMan]

Now-dead system:
i5-3570K
Asus P8Z77 MB
Corsair Venegeance RAM 4x4GB
EVGA GTX 580
Seasonic X-750 PSU
Seagate Barracuda 2TB disk
Lite-on Blu-Ray/DVD recorder optical drive
Antec P280 case

OK, I just put together the new system above and was doing some folding for its burn-in period. It went about 2 days of this without any problems (other than one bluescreen before I got the MB BIOS updated). Last I had checked, CPU was running 43-45C at full load, non-overclocked.

Then, my daughter was using the system (playing some web game while the folding was going on in the background), when she heard a very load POP! sound and the PC died.

Now, the system won't power up at all, none of the fans spin up, no POST happens: no error beeps, no problem indicator LEDs light, it's just dead. I'd think it was the PSU, but there's an always-on power LED on the MB that remains lit, so the MB is at least getting some bit of power.

The case was fully opened up and sitting on the desk next to her (with the underside of the MB facing her). I asked if she could tell around where the POP noise came from (hoping she'd point towards the PSU), but she pointed right around where the CPU is. There's a lot of caps on the MB around there, so that's my best guess as to the POP sound.

I pulled the heat sink, RAM and vid card out, but there's no obvious damage anywhere on the MB. I haven't removed the CPU, but the top side of it looks undamaged. Doing a sniff test, there's no obvious burn smells from any one spot, but it had a few hours to air out before I was able to get in there.

I'm guessing the POP was from one of the capcitors on the MB surrounding the CPU area, and not from the CPU itself or the PSU, so I'm inclined to just return the MB and then proceed from there. But before I do, am I missing anything? Maybe it's not the MB? Is there a better way to proceed?

Thanks!

 

[Blain]

1. Test the system as it is with a known good PS.
2. If that fails, remove the HS, memory and everything from the MB (I've leave the CPU for now).
Inspect it for signs of burnt components (smell might help you if you can pull the MB).

 

[LintMan]

I had already tried #2 and found no signs of burnt components.

I was reluctant to start swapping components, because to test the MB, I'd have to essentially gut my other PC, which I didn't want to do. But trying the known good PSU in the problem system was a great idea since I only had to pull a few power cables to try it. I should have thought of that but was too fixated on it being a MB problem.

And it turns out, that the system lights up the diag LEDs and beeps like crazy with the known good PSU (the system had no ram, video or hsf), while it just sits there with the new (and apparently bad) PSU. So even though the PSU is working enough for the MB to light the power LED on the board, it's not working well enough to actually let the MB run its POST.

So there we have it, bad PSU. I've got an RMA started up at Newegg, which <grumble grumble> is going to cost me $18 return shipping, and annoyingly, Newegg won't cross-ship.

Anyway, thanks hugely for the great idea. That saved me from returning the wrong component