Computer restarting, killing power supplies.

[GotNoRice]

I built a computer for some family friends a few years back and in January they let me know that it had started to turn off and on by itself. At random intervals it would spontaneously turn completely off. It would also turn on by itself during the night; also go into reboot cycles, etc. That particular job ended with me simply dusting the computer out, which hadn’t happened in years. It had pounds of dust inside, which combined with their smoking habit really created some nasty dust bunnies inside. It looked like the massive amounts of dust, particularly in the power supply, was causing it to sort of cook itself to death and cause voltage drift on the rails. I recommended that they replace the power supply, but since the dusting effectively fixed the problem (at least temporarily) and they are sort of cheap people they just left it at that.

That lasted until recently, when the computer began to act up again in a similar fashion, finally resulting in registry corruption on the hard drive. I replaced the old 300watt powersupply with a 380watt Raidmax, repaired the registry corruption, and everything seemed fine. Two days later after taking the computer back, the Raidmax powersupply died also. I’ll be the first to acknowledge that Raidmax makes POS powersupplies but this is a 2.8ghz northwood P4 with integrated video that pulls 60-100watts according to my kill-a-watt meter and it should not be beyond the capabilities of that PSU.

I took the powersupply back and exchanged it for a 450watt powersupply that cost $10 more, put it back in the computer again, and took it back to the house again. Again after about a day or so the computer started to shut down and start up on its own.

I have to admit at this point I’m sort of stumped as to what could be causing the problem here. Having the same issues with three different power supplies, it would seem to indicate that it’s either a problem with the motherboard or maybe with something electrical in their house?

 

[Shmuckety]

Are the temps ok? Did you test the ram? There is nothing you can do about their electrical, short of getting them a UPS. Are all the fans still alive? Maybe there is a short. You should check the above and then if that is not the problem take it completely apart, clean and put it all back together.

 

[Spartacus]

It's possible that there are bads caps on the mobo that are "partially shorted". I used to see stuff like that on equipment I serviced years ago. The bad caps cause a very high load on the PSU and kill it.

I'm not saying that's what it is for sure, but it's possible.

I go along with the suggestion of disassembling the system and checking everything over carefully.