Why do my computer's power supplies keep dying?

March 23, 2009 3:45 PM

My desktop computer's power supplies (three thus far) keep overheating and then fail permanently -- but only when they are plugged in through a power strip (i.e., everything is perfectly fine when the computer is plugged directly into a wall outlet).

I finally realized that solution, though have no idea as to why it should make a difference. That is, if not plugged directly into an outlet, any power supply (PSU) in my computer will, within a few hours, overheat to the point of failure and, from that point on, will be non-functional for the rest of eternity. This has me befuddled, and so I ask:

Is this (a) a short and/or (b) a grounding issue? Or, more to the point: (c) why would the addition of a power strip [power bar] have such a negative impact, even if it is one of these issues? Do power bars ground things differently (I know nothing about these things)? (Also: this has happened using different power bars, so I'm assuming that it was not those particular power bars per se, but that it has something to do with power bars in general, plus the electrical oddities of my desktop computer.)

posted by astrochimp to computers & internet (13 answers total)

Do they fail with the SAME power strip? If so toss the power strip.
posted by wfrgms at 3:48 PM on March 23, 2009

this has happened using different power bars,

Doh!

It's an odd problem you have. I mean I see dozens of PSUs plugged into even very sketchy power strips or extensions every week and seldom see a fail.
posted by wfrgms at 3:49 PM on March 23, 2009

Weird. That shouldn't happen.

Thoughts:

1- Power strips are indeed bad. Perhaps they are surge protecting models, whose surge protection elements have burnt out? (That happens.) Check the continuity/resistance of each leg? Are the power strips the same brand/manufacturer? Maybe they were put together wrong and the hot/neutral keying is wrong.

2- When you plug the computer into the power strips, is it the only device on the strip?

3- Are you using the exact same outlet, just with or without the power strip? (Thought being that there is some device on that circuit that is making the power on it unclean. But when you plug directly into the outlet, you use a different outlet that's not [as] susceptible?

4- The voltage in your house is unacceptably low, and the addition of the added resistance in the longer cable and extra connections forces the power supply to work too hard and overheat? Check the voltage of your power.

A test would be to get an extension cord and plug the computer into it, and then into the "known good" outlet. This would rule out or in some of the possibilities.
posted by gjc at 3:57 PM on March 23, 2009

What about air circulation for your power supplies? Is it right against a wall? Is it rebreathing its own heat? What wattage are your power supplies and what are you running on it? Is it designed to handle the video card(s) you're using?
posted by furtive at 4:01 PM on March 23, 2009

Thanks for your responses so far. gjc, my answers to your questions are as follows:

1- Two PSUs were burnt out on a surge protecting model, one PSU on one of those 6-outlet adapters you plug into a standard outlet (and not of the same manufacturer).

2- It probably also had a monitor and speakers plugged into it. However, I moved across the country only bringing the desktop case, and this has happened with different monitor and speakers.

3/4- Different houses, different outlets (and with different monitor/speakers/etc., I'm especially confused).

furtive, thanks, too: air circulation is fine (or unchanged between power strip replacements), and never right up against a wall (usually one foot away). Wattages were between 300w and 400w, which should be more than sufficient for my video card (and none of these cases involved any heavy use of the card at all -- just the windows desktop, idling quietly).
posted by astrochimp at 4:08 PM on March 23, 2009

As an addenda: when I mention everything is fine when plugged directly into a wall, I mean that I went 1-2 years like that (including hours upon hours of heavy graphics usage from 3D games), with no problems at all.
posted by astrochimp at 4:12 PM on March 23, 2009

Tell us a little more about your setup, manufacturer, wattage and what processor and video card(s) you have (to estimate load).

Not all powersupplies are built the same, some vary dramatically in their effeciency depending on the load. Silent pc review does real testing on psu's.
posted by zentrification at 4:35 PM on March 23, 2009

Manufacturer: me piecing together various parts.
Wattage: 300w to 400w or so, depending on which PSU it was that died.
CPU: Athlon XP 2500+
Mobo: Gigabyte GA7-VAX
Video: Geforce FX5600
A couple of hard drives and a cd burner.

N.B.: in the first instance, the setup had been running fine for perhaps over a year. Then, with the addition of a power strip, it ran fine for perhaps over two hours. Then it shut off, never to be powered on again (until replacement of PSU).

In the second instance, the PSU lasted for about two hours total, because I hadn't realized that the power strip was doing less than wonderful things for me.

In the third instance, setup was precisely the same, it ran for maybe a year until, oops, stupid astrochimp forgets that he should probably plug it directly into a wall socket, and goes and plugs it into one of those six-socket deals that you plug into a standard outlet. PSU runs fine for a while (maybe even a whole day), dies.
posted by astrochimp at 4:49 PM on March 23, 2009

I'm wondering if you are just having a wicked case of coincidence. Power supplies were shaky, but working. When they got unplugged and repowered, it pushed them over the edge.
posted by gjc at 5:11 PM on March 23, 2009

I'm by no means an expert, but I blew out my computer's power supply and lost a power strip due to dirty power. I bought a power conditioning unit online for about 50 bucks and haven't had any problems since. You could buy a voltage tester to test the outlet and see if that's the problem first.
posted by antonymous at 5:56 PM on March 23, 2009

2nd'ing coincidence. What kind of power supplies are you buying? I've had 5 cheapo generic PSUs go out on me within hours of unpacking. Now I pretty much stick with Antec.
posted by wongcorgi at 7:25 PM on March 23, 2009

Yeah, dirty power or the cheapo-factor of the PSUs I tend to get might be it. Or coincidence.

However, the fact that I've had cheapo PSUs in tons of different systems yet nary a similar problem makes me suspicious (and I've run through lots of computers). I hope this particular computer isn't just cursed...
posted by astrochimp at 7:29 PM on March 23, 2009

I'm going to go with either: wild coincidence, or the extra resistance from powerstrips hypothesis.

Get a voltmeter that can handle 120V AC and check out the voltage on your outlet.

Also, send the burned-out PSUs back to the manufacturer and see what they say.
posted by zippy at 9:06 PM on March 23, 2009