Thread: Will a weak PSU cause my PC to restart at random?

I'm having a bit of a problem with my PC and I'm not sure how to go about finding the cause of the problem so I can fix it. I'll start from the beginning.

My husband and I usually keep our PC on 24/7 because we've had problems in the past about it going to hibernation mode and not wanting to come back out. Well about a month ago everything was running fine (we even bought and nice new energy star LCD 21" screen), then as we we're watching TV we heard a loud "pop" noise come from out PC followed by a burning smell. We checked it and didn't see any problems and it continued to run fine and nothing caught fire. It still ran fine a few days later but then it started to reboot itself at random times. More annoying then anything and we still weren't seeing any problems whenever he ran a check on the system. We though it was caused by low ram and got a couple gig sticks which would have been more then enough for what we run. But the problem continued. He reinstalled some video drives and when that didn't help he reformed the HD. Still nothing. So he restored the whole system. It seems to work for a few hours and just when we thought we'd fixed it, it restarted again! I got to thinking that maybe it has something to do with the PSU, but I'm not sure what is causing it. Today as it restarted on me for about the ninth time, it turned the keyboard off on the restart. It did this twice (the keyboard is wired to the front usb) on the last two restarts.

Does anyone have any idea what might be happening? And what short of buying/building a new PC can I do that is cost effective?

Thanks!

Yes, a PSU could cause that. The PSU has a small circuit inside that monitors the voltage outputs. If one of the outputs drops out of tolerance, the PSU is supposed to automatically shut down. When it does, it removes a control signal called something like "PowerOK". When that happens, it forces an automatic hardware reset.

If the PSU does not shut down, really bad things can happen such as exploding components or flames.

And with the system specifications, we can offer recommendations about appropriate size. Include any prospective upgrade plans also.

I would guess that what you heard was a capacitor failing. Surprising is that your system is still running after the component failed.

I recommend changing the PSU as soon as possible and not using the system until it has been replaced.
When caps fail in low end PSUs (if your system is a prebuilt one it most defiantly is) the voltage output gets very unstable and will kill your system with prolonged use.

If you would post the model of your computer we can direct you towards a quality replacement PSU and instruct you on the proper procedure for replacement.