Careful with how you store your old PSUs

pelago · Post by **pelago** » Tue Mar 20, 2007 3:22 am

This is pretty obvious when you think about it, but it caught me out: I just killed a perfectly good PSU. As soon as I plugged it in it went poof and smoke came out. The PSU had been stored in my random 'computer bits' box into which I chuck all sorts of things, and I think a screw or other small metal part must have got into the PSU and shorted out something.

From now on I'll keep unused PSUs in plastic bags or similar to stop bits falling into them.

amjedm · Post by **amjedm** » Tue Mar 20, 2007 4:04 am

If you have them in a cold room I believe you also need to let them warm up before switching them on otherwise the fuse might blow?

jhhoffma · Post by **jhhoffma** » Tue Mar 20, 2007 5:01 am

amjedm wrote:If you have them in a cold room I believe you also need to let them warm up before switching them on otherwise the fuse might blow?

Well, they don't really have fuses, but if any electronic devices are colder than the dewpoint of the environment they're in, condensation can form and short out electrical components. That's when you get the smell.

Sometimes, it just happens with old equipment, especially if it hasn't been used in a while. Components wear out and the shock of a sudden startup at high draw cause the component to go poof.

xzorby · Post by **xzorby** » Tue Mar 20, 2007 9:41 am

They do actually have fuses.. Or at least the ones I have lying around here do.

mantralord · Post by **mantralord** » Tue Mar 20, 2007 10:26 am

Yeah, the fuses are usually on the input stage in place of actual over current protection. Also keeping the PSU seperate of other components is good advice.

amjedm · Post by **amjedm** » Tue Mar 20, 2007 12:02 pm

I have seen at least one fuse in a cheapy psu. Replacing it didn't help once it blown.

pelago · Post by **pelago** » Wed Mar 21, 2007 1:50 am

In my case it hadn't been stored in the cold. It was a decent Antec PSU. It's been unused for about a year. I haven't bothered opening it up to see if it's just a fuse that has blown - the flash of light and smell/smoke afterwards made me pretty sure that it's more than just a fuse!

jaganath · Post by **jaganath** » Wed Mar 21, 2007 2:00 am

I haven't bothered opening it up to see if it's just a fuse that has blown - the flash of light and smell/smoke afterwards made me pretty sure that it's more than just a fuse!

um, isn't a flash of light and smoke exactly what you would get if it was a fuse? I'm no electrical whiz, that's why I ask...

pelago · Post by **pelago** » Wed Mar 21, 2007 2:15 am

Hmm, maybe you're right, I'm no expert either...

Bluefront · Post by **Bluefront** » Wed Mar 21, 2007 3:56 am

Most types of fuses don't smoke when they blow......so something else probably burned. Not surprising anyway. My experiences with Antec PSUs has been all bad.

amjedm · Post by **amjedm** » Wed Mar 21, 2007 4:05 am

Bluefront wrote:...My experiences with Antec PSUs has been all bad.

Not just you, a few others as well...

jhhoffma · Post by **jhhoffma** » Wed Mar 21, 2007 5:14 am

Strange...I've never seen a fuse in any of my PSU's and I've owned some cheapo models in my time.

I guess I assume all PSU used active over-current circuit protection.

From my other experience with high-power electronics, I would concur that you wouldn't smell the fuse blowing, what you'd smell is the coils or transistors melting behind it.

Elixer · Post by **Elixer** » Wed Mar 21, 2007 6:04 am

I've never seen a power supply that didn't have a fuse. It's very common though for them to be just straight soldered to the circuit board and so they look like a big white resistor to the untrained eye. The reason they're not replaceable is because the fuse exists not to protect the power supply, but to protect the power lines in case the power supply blows. In other words, if the fuse blows, you're power supply is already screwed and so there's no point in having a replaceable fuse.

Forumlurker · Post by **Forumlurker** » Mon Mar 26, 2007 7:39 am

I did have a old power suply that did flash and smoke, it was a chock. But the power suply worked just fine. I quit sure it was the dust that cough fire, was testing it out side the box to see if it worked.

vincentfox · Post by **vincentfox** » Wed Mar 28, 2007 11:24 am

Another point I have is long-term storage. People think they have some 10-year old PSU they are going to finally make use of it, might be surprised that it might no longer be good. Electrolytic capacitors are filled with a substance that ages, cracks, and degrades over time even if you aren't using it. Active usage in high-heat environments accelerates the process. But even just sitting on a shelf, well eventually it'll become useless just like a dusty Lithium-Ion battery.

I wonder if anyone makes a PSU with solid-state caps for longer-term usage?