Is my power supply dying?

Mark Hamilton · 08-09-2003, 04:36 PM

I think the power supply in my parent's desktop PC is dying. Sometimes the machine won't boot at all (blank screen) and other times when it does start it will die completely just minutes after Windows starts. Other times it will hard reboot for no reason and at others will reboot, start booting, reboot, start booting, etc.

Is this the power supply? From time to time I'v also heard a high pitched squeling during the machine's initial boot.

It's a pretty basic machine (AMD Duron, 256mb of ram, etc.) Nothing is overclocked, the machine is in the basement (which is rather cool) and there are no signs of excessive dust in the machine.

Is it likely the power supply? If so, I'm going to need to get a new one ASAP as this downtime is a pain as my parents have, surprisingly, become quite dependant on this machine.

As always, thanks for your time guys! ^_^

Mark

Mark Hamilton · 08-09-2003, 05:07 PM

Steve Berger · 08-10-2003, 11:11 AM

Have you done all the obvious things ? Re-seat all the cards , memory chips , cables , connectors , CPU (especially if it's a tower with a large heat sink hanging on it) . Check all the fans , including the one in the power supply . If the P/S fan isn't running you may have indeed have a damaged power supply.

Beyond those types of things almost anything could be the culprit and a substitution and/or removal process of components is in order.

Recently a friend had this type of problem which turned out to be the on-board video chip not being activated because a damp environment had caused some corrosion in the (empty) AGP slot. The bios thought there was a card in the slot and tried to use a non-existant video card. Installing , then removing a standard video card cleaned the contacts makig it work again.

Mark Hamilton · 08-10-2003, 12:45 PM

Thanks for the tips,

Yup, everything is seated correctly, there is certainly no moisture around and the computer is plugged into a decent external power bar. I disconnected all of the internal components from the power supply and booted into the BIOS. It sat there for a long time without any issues. I recconected all of the components and then booted into Windows XP in safe mode and it ran signficantly longer before rebooting, at which time it tried to start up, rebooted, tried to start up, rebooted, etc.

I guess I'll keep on looking.

Thanks again.

Glenn Overholt · 08-10-2003, 05:41 PM

Not good. I don't suppose that you can recreate the high-pitched squeal, can you? If you put your ear next to the power supply you'd be able to be sure that was it.

I don't see how a power supply can still run. I thought they were just go/don't go devices, and if the motherboard got a voltage that was out of whack, it would shut down, but it wouldn't start back up, and that would be that.

Could you try running it with only the hard drive connected? Unplug everything else, and don't worry that the OS goes weird and starts asking where this is, and so on. See how long it runs that way.

If it is the same high-pitched squeal that I remember as a kid, they were capacitors that wound up with too much voltage, but then they would explode! Are there any dark parts or spots on the motherboard?

Glenn

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nolesrule · 08-10-2003, 05:54 PM

I've had failing power supplies before and that sounds like the symptoms of one.

They aren't go/no-go devices. They can work intermitently once they start to go.

Glenn Overholt · 08-10-2003, 10:25 PM

Ok. Mark, make sure you get the dimensions and wattage before you get another one. It sucks getting the wrong size.

Glenn

nolesrule · 08-11-2003, 12:14 AM

I would suggest going for at least a 350W power supply, but I have 400W in all my boxes. The most common causes of power supply failure are overheating from a dead fan OR not having enough juice to power the system.

And the reason power supplies can go over time is that when they start to go, you ususally just get a voltage decrease on one of the 3 voltage levels that computers need. When the decrease is still within tollerance, the power supply will work, but when it drops too far, you'll get a reboot or a cut-off.