How old would a PSU have to be to be considered too old?

I have an Enermax 420w psu that I purchased around 10 years ago that is still alive and kicking after all these years. I use it in my htpc right now, but it is very loud so I thought about switching it to my server. The server has a corsair 430w psu that is dead quiet. Do I have anything to worry about using a psu that old or should I just get a new one and put this old timer on the shelf as a backup?

You might open it up (carefully) and visually check for any bulging caps. Check the rails with a multimeter to make sure they're still in spec. Other than that, there's no easily discernible reason why it shouldn't keep on trucking. I wouldn't replace it unless you need to.

That is what I would do. If you don't touch anything shiny inside it won't kill you. Touching shiny things opens you up to draining a 400v capacitor, an activity I recommend against.

i have power supplies from 1994 that still work no signs of damage internally so what hey. Check it and be ESD smart about it.

I'll open it up, but it has been in use 24/7 for the past 2 years so I'm going to guess it's ok. I'll make sure once I take it out. Thanks guys.

Some power supplies (and other electronics) made around the year 2000 had faulty caps that were prone to bulging and failing prematurely.

Quality PSU that aren't affected by inferior caps can last a long time. If the noise is caused by fan, replace the fan. If the voltage are more than 5% off spec, probably retire it.

I typically retire my older PSU into an older PC then run it until it or something else dies.

I'd say make sure if it DOES got out with a "Bang" make sure it is not in a "critical" type system - or a system that isn't BACKED UP elsewhere. A PSU failure can cause all kinds of collateral damage in the form of borked drives, fried MoBo's, dead RAID Cards, etc.

While I've had PSU's last 10 years myself, I've also seen a nice 4-5 Year old PC Power & Cooling shoot sparks into my DAW PC - and brought a recording session to its knees in a hurry!!! Luckily, no hardware was lost in the ordeal, and the data was all intact (weren't actually rolling on a take when the PSU failed).

I consinder that DAW PC fairly "Mission Critical" for my Studio - so I will be swapping the PSU in it once every 3 years or so (and I'm running a nice Seasonic - but after 3-years - I'll swap it w/o blinking). Granted, there is still "Infant Mortality" to consider with any hardware - but that's why I'd be inclined to thoroughly stress-test any PSU I'll be using in a "mission critical" system before it goes into service.

I, personally, would NEVER use a 10 year old PSU in any system I need to rely on - but I'm somewhat anal about my "uptime" and backups in general - even on test PC's and such.

Caps DO dry-up when they get old - and those can not be detected by sight as they don't "Bulge". Only truly defective caps or caps that are run out of their specs will "bulge". Otherwise, more in-depth analysis is needed to determine their performance/longevity - and Caps aren't the sole point of failure.

It's your system - only you can decide how critical it (and the data contained within) are to you...

Open that PSU up and carefully check for any kind of damage like caps and that stuff. And as Bob said, do not touch anything shiny. 400v are kind of scary.

If everything is correct, check voltages with a DMM. If they are within spec, keep the PSU.

Then replace the fan with a new one if it's loud. Or lubricate it.

Just FYI, I bet you could get a decent (not a total piece of crap) power supply off newegg or maybe even at your local best buy for under $50... maybe even under $30.

That said, I have a couple AT power supplies that still supply perfect voltages, are quiet, and have zero issues to complain about. One from 1994 and one from 1998 or so, and I know I've had some from the late 80s that also worked fine. Like said above, I'd just avoid the early 2000s models with inferior capacitors.

I'd check for leaks, and make sure the voltages are within spec using a multi meter. Can't hurt anything.

Deathhorse said:

i have power supplies from 1994 that still work no signs of damage internally so what hey. Check it and be ESD smart about it.

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For the love of god.....do NOT use a grounding strap while working in a PSU. You do NOT want to be the active ground for a charged capacitor!

If reaching inside the unit, use only one hand....your right hand. If you touch something that you shouldn't there's less of a chance that the charge will go through your heart.

Ideally, if you're not trained to repair electronics and are concerned about the status of your old PSU, just replace it. It's much cheaper than a trip to the hospital, or heaven forbid, a funeral.

*EDIT* - You don't have to worry about voltage as much as current. Amperage is what kills. (Think 50,000v stun gun.)

You can't have amps without volts, the human body and human skin are both resistors. A single AA battery can put out well more than enough amps if given a dead short, but good luck trying to kill yourself with one.

Ground straps (halfway decent or better ones, at least) have a 100k or 1M ohm resistor in series with them to keep the current low as well.

Regardless, opening a PSU isn't the worlds greatest idea, but if you don't touch anything shiny you'll be fine. It'd be pretty hard to do yourself in without taking the PCB out of the PSU case, too.

Most old (10-15 years old) PSU's will get weaker with time but if you don't have startup problems or other unexplained restarts then it should still be fine. But not putting out all the watts it used to. The fans are most likely to go first if it's been running long so you might want to check that out. Capacitors are dangerous to work with if they are fully charged, however they will drain over time (could be days, weeks even years) but if you want to be on the safer side let the PSU rest without power for a week or two before opening to reduce any chances of misshaps.