Question Do PSU capacitors age/burst even when a PSU is not being used/unplugged?

[Turbonium]

I have some older rigs that have been in boxes/storage for around 6-7 years now. I also have a few PSUs that have been in storage on their own (one of them being factory sealed, in fact), two of which I'm trying to sell on eBay.

I'm just wondering if any of the PSUs may be an issue; could any of the capacitors (which I understand are the first things to go in a PSU) be on the way out (or already gone)? Or do PSU capacitors only age/burst at significant levels if they're being used?

(I did some quick googling, and it seems the capacitors may indeed be in bad shape - could use some clarification.)

 

[VirtualLarry]

Well, hmm.

I've read that capacitors last longer (electrolytics) in PSUs, if there's a slight charge on them.

So, in that line of thinking, "BNIB, unused" PSUs may go bad SOONER than used PSUs. Of course, usage at higher levels implies a certain amount of wear & tear too.

I had a pair of Antec 750W 80Plus Gold EDG (EDGE?) PSUs, that were picked up cheaply on Newegg when they were clearing them out, and stored BNIB for a number of years, and then opened up and used.

Mostly, so far, they've been OK, but I do wonder a bit.

Got one powering a 5x GTX 1660ti mining rig, each power-tuned to use only 75-80W, card + riser, plus mobo / CPU / RAM / SSD / etc.

Also have the other one in my main rig, with dual GTX 1660 Super cards (power tuned) and mining on them and a Ryzen R5 3600 CPU. Previously, I had an RX 5700 and RX 5700 XT reference card mining, power tuned to around 130-150W ea.

So not stressing them too much, they've held up, even after being in storage for probably nearly five years. Active service for at least a couple of years, I suppose.

 

[Turbonium]

What's the best way to check PSU health nowadays? Beyond a visual inspection of the capacitors I mean, and software monitoring of rails (I could use a refresher).

As for the PSUs listed on eBay: I'm going to make it clear that they've been in storage for years, and that they're being sold as-is, with no guarantees. Hopefully that should be enough.

 

[Hail The Brain Slug]

What's the best way to check PSU health nowadays? Beyond a visual inspection of the capacitors I mean, and software monitoring of rails (I could use a refresher).

As for the PSUs listed on eBay: I'm going to make it clear that they've been in storage for years, and that they're being sold as-is, with no guarantees. Hopefully that should be enough.

Without being able to stress test a PSU with a dummy load to ensure its still capable of giving the rated power without dropping voltage or shutting off, there's not much you can do.

Maybe throw up some stress tests to load your PC as much as possible and make sure nothing funny happens and your voltages are OK. Software monitoring isn't the most reliable for this, it would be better to plug in a spare cable and probe it with a multimeter to check the 12v line.

 

[Soulkeeper]

Electrolytic capacitors tend to have a "shelf life" or mtbf. The clock starts ticking from the time they are manufactured. The problem is this time can vary wildly between brands and types as well as operating conditions. And the time can be much more or less than the manufacturer lists.
If a device is stored unused for a long period of time they could degrade or "dry out", in which case the initial power up might be the most likely time to observe failures.
I've heard from several sources that regular use is better than leaving them unused or seldom used.

As far as a psu goes, there is no way to really guarantee a device is good without doing a thorough round of tests on all the output rails under different load conditions. You would be checking that everything conforms the the atx specification essentially.
Many people would typically just plug an old psu in and if no instability was observed they'll just assume all is good. I guess this is ok in most cases. A good motherboard should have overcurrent/overvoltage protection and should survive most failure cases. You're likely to observe random power downs or difficulty getting the system to post.

 

[mindless1]

Dodgy Chinese capacitors will rot just sitting on a shelf due to an instable electrolyte formula that breaks down. Better (still somewhat junk) Chinese capacitors won't, and their lifespan is more a matter of internal resistance causing heat during use, and the same is true for quality Japanese caps but they tend to have lower internal resistance (ESR) if a suitable part is selected for the application.

After sitting for these years, the oxide layer in the cap has degraded some and through a few hours of use will be reformed, I mean for the electrolytics, solid caps don't have this issue. Performance maintaining low ripple may be compromised during this reforming process, but these days most components in a PC, step down the voltage from the PSU to something lower anyway and excessive ripple is more a matter of a slight stability decrease rather than damaging levels.

So what I would do is turn the system on, leave it idling in windows (not bios, so at windows power managed low power state) for a few hours instead of immediately going full bore into high load stress testing or gaming, etc.

Odds are that they are fine to reuse, with their lifespan depending more on hours already used, particularly at high load, but you might want to relube the fan(s) if any are sleeve bearing.

If you wanted to be extra paranoid or cautious, you could instead power them up jumpering the PS-On pin to ground, powering a slight 12V load like an old HDD and just leave that running a few hours and measuring voltage instead of subjecting a whole system to it, but I've powered up many old systems after years of storage and never had this be a problem, mostly they just needed a new battery and a few stored in a basement needed cobwebs cleaned out.

At the same time, remember what I stated about some dodgy chinese caps failing just from sitting, which means if any are on a video card or motherboard they may have failed from sitting this long too, but otherwise will also improve from reforming the cap oxide layer from a few hours idling along. This sitting shelf rot issue was mostly seen in the early P4 and Athlon or older era.

 

[DIY_Computer]

Dodgy Chinese capacitors will rot just sitting on a shelf due to an instable electrolyte formula that breaks down. Better (still somewhat junk) Chinese capacitors won't, and their lifespan is more a matter of internal resistance causing heat during use, and the same is true for quality Japanese caps but they tend to have lower internal resistance (ESR) if a suitable part is selected for the application.

After sitting for these years, the oxide layer in the cap has degraded some and through a few hours of use will be reformed, I mean for the electrolytics, solid caps don't have this issue. Performance maintaining low ripple may be compromised during this reforming process, but these days most components in a PC, step down the voltage from the PSU to something lower anyway and excessive ripple is more a matter of a slight stability decrease rather than damaging levels.

So what I would do is turn the system on, leave it idling in windows (not bios, so at windows power managed low power state) for a few hours instead of immediately going full bore into high load stress testing or gaming, etc.

Odds are that they are fine to reuse, with their lifespan depending more on hours already used, particularly at high load, but you might want to relube the fan(s) if any are sleeve bearing.

If you wanted to be extra paranoid or cautious, you could instead power them up jumpering the PS-On pin to ground, powering a slight 12V load like an old HDD and just leave that running a few hours and measuring voltage instead of subjecting a whole system to it, but I've powered up many old systems after years of storage and never had this be a problem, mostly they just needed a new battery and a few stored in a basement needed cobwebs cleaned out.

At the same time, remember what I stated about some dodgy chinese caps failing just from sitting, which means if any are on a video card or motherboard they may have failed from sitting this long too, but otherwise will also improve from reforming the cap oxide layer from a few hours idling along. This sitting shelf rot issue was mostly seen in the early P4 and Athlon or older era.

I'm curious about this topic as well, after you warm the caps up by ideling in windows, will they be nearly as good as the day you bought the unit? And how long could you store a mobo/psu/gpu before you would have major problems trying to use it because caps? 10 plus years? 20?

 

[Soulkeeper]

There is no fixed time for such things, just estimates and ratings. Given 100 components with a 10,000hr rating, for example, you might have 90 of them perform perfect for 10,000+ hours and 10 might fail after only 5,000hrs.
Luck of the draw essentially. And the ratings are done under specific scenarios ie: temperatures, voltages, frequencies. Deviating even slightly from those scenarios could turn that 10,000hrs into <5,000 quickly.
Modern components are manufactured under much more consistent/reliable conditions than in the past. You might see 99% of them all perform essentially identical.
Going any deeper delves into the chemistry of the actual components and gets technical quick.
I've got a few quality electronics from the 1980's that still work fine. Although i'm sure they might be slightly off on their voltages or behavior, they still function.
I'm sure many new mobo/psu/gpu would function fine 20yrs from now if stored in a cool dry place. The failure rate is almost certainly higher, after such prolonged storage, however.

 

[DIY_Computer]

There is no fixed time for such things, just estimates and ratings. Given 100 components with a 10,000hr rating, for example, you might have 90 of them perform perfect for 10,000+ hours and 10 might fail after only 5,000hrs.
Luck of the draw essentially. And the ratings are done under specific scenarios ie: temperatures, voltages, frequencies. Deviating even slightly from those scenarios could turn that 10,000hrs into <5,000 quickly.
Modern components are manufactured under much more consistent/reliable conditions than in the past. You might see 99% of them all perform essentially identical.
Going any deeper delves into the chemistry of the actual components and gets technical quick.
I've got a few quality electronics from the 1980's that still work fine. Although i'm sure they might be slightly off on their voltages or behavior, they still function.
I'm sure many new mobo/psu/gpu would function fine 20yrs from now if stored in a cool dry place. The failure rate is almost certainly higher, after such prolonged storage, however.

Would using them every couple years help prolong lifespan? Or will just leaving stuff in a box for many years be fine? Some stuff is just backup parts and such so I won't use it until something breaks.

 

[Soulkeeper]

That's impossible to say for sure, but i've heard many audiophile people swear by the idea of periodically powering up old hardware (specifically mentioning the old caps). I'm sure it varies by exact type, series, manufacturer, age. I doubt the difference, either way, would be substantial for any scenario.

 

[DIY_Computer]

That's impossible to say for sure, but i've heard many audiophile people swear by the idea of periodically powering up old hardware (specifically mentioning the old caps). I'm sure it varies by exact type, series, manufacturer, age. I doubt the difference, either way, would be substantial for any scenario.

I saw these power supply testers on Amazon,https://www.amazon.com/Thermaltake-...=p_85:2470955011&rnid=2470954011&rps=1&sr=8-4

https://www.amazon.com/Kingwin-Computer-Supply-Tester-Digital/dp/B07VVTVRYT/ref=mp_s_a_1_2_sspa?dchild=1&keywords=power%2Bsupply%2Btester&qid=1633679233&refinements=p_85%3A2470955011&rnid=2470954011&rps=1&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzSkxTMlVUWFdMOEVIJmVuY3J5cHRlZElkPUEwODYzMDIzSEtOOE9SVDIzRVEzJmVuY3J5cHRlZEFkSWQ9QTA1MjQ3NjkxR0tKWFZRMDAzTkhWJndpZGdldE5hbWU9c3BfcGhvbmVfc2VhcmNoX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1

Would these be useful to reform caps after many years of storage? I know there's a paper clip method too but this seems simpler. So the psu warms up and dosnt immediately get hit with normal load on a mobo and bust? If the psu spec changes I will need my old psus for my old boards.

 

[mikeymikec]

Dodgy Chinese capacitors will rot just sitting on a shelf due to an instable electrolyte formula that breaks down.

I've seen this happen with a Gigabyte Athlon XP era board. It started having stability issues that I couldn't narrow down to a part that I could replace, so I ended up selling the customer a rebuild. At the point that decision was made, the capacitors looked fine. I kept the board for another six months I think, and by then some capacitors had started to leak.

 

[DIY_Computer]

I've seen this happen with a Gigabyte Athlon XP era board. It started having stability issues that I couldn't narrow down to a part that I could replace, so I ended up selling the customer a rebuild. At the point that decision was made, the capacitors looked fine. I kept the board for another six months I think, and by then some capacitors had started to leak.

have caps gotten better since then? beacause that was a long time ago.

 

[mikeymikec]

have caps gotten better since then? beacause that was a long time ago.

Yes, I'd say so. The newest board I recall seeing a leaky capacitor on was the other day actually 🙂 A customer with a Core 2 Quad (so around 2008) ASRock board.

Nothing made since 2010 that I can think of.

 

[Soulkeeper]

I saw these power supply testers on Amazon,https://www.amazon.com/Thermaltake-Automated-Supply-Oversized-Supplies/dp/B005F778JO/ref=mp_s_a_1_4?dchild=1&keywords=power+supply+tester&qid=1633678988&refinements=p_85:2470955011&rnid=2470954011&rps=1&sr=8-4

https://www.amazon.com/Kingwin-Computer-Supply-Tester-Digital/dp/B07VVTVRYT/ref=mp_s_a_1_2_sspa?dchild=1&keywords=power%2Bsupply%2Btester&qid=1633679233&refinements=p_85%3A2470955011&rnid=2470954011&rps=1&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzSkxTMlVUWFdMOEVIJmVuY3J5cHRlZElkPUEwODYzMDIzSEtOOE9SVDIzRVEzJmVuY3J5cHRlZEFkSWQ9QTA1MjQ3NjkxR0tKWFZRMDAzTkhWJndpZGdldE5hbWU9c3BfcGhvbmVfc2VhcmNoX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1

Would these be useful to reform caps after many years of storage? I know there's a paper clip method too but this seems simpler. So the psu warms up and dosnt immediately get hit with normal load on a mobo and bust? If the psu spec changes I will need my old psus for my old boards.

Those seem to just verify voltages, probably nothing more than what you could do with a multimeter.
They don't appear to put load on the rails or check anything else.
Someone with a nice shop might put load on each rail ie: 10% 50% 100% and check/scope the voltages.
I guess they could be usefull, just not thorough by any means.

 

[mindless1]

You don't need to load the rails of the PSU, unless the particular design requires an external load to stay turned on. It's not heat but rather voltage which reforms the oxide layer, so a paperclip, or PSU tester (small/simple type that doesn't apply much load) would be fine.

There's even a school of thought that the *best* way to do this is you take the caps out of the circuit and apply a minimal voltage then slowly raise it over time, but this is more for preserving components in vintage equipment. If I had a PSU or mobo cap out of circuit anyway then I'd just buy a new one and replace it.

There are too many variables in cap design, circuit design, equipment design to state some rule of thumb for how often equipment should be powered on, more than "every few years". Most PSU and motherboards should be fine for a decade or so if you do as suggested, just power it on into windows/other OS with it idling along at a relatively low output for a few hours. I state this from historical evidence of people reusing old systems but cap design changes, board design changes, again variables between something from yesteryear and today's components.

Caps on newer equipment can fail from bursting too, just a matter of time and heat exhausting their lifespan. Not to point fingers but the Chinese are notorious for over-spec'ing things so that one variable can make a lot of difference. Cap failure is still common in low end PSU especially, low enough end that the better advice is don't use a junk PSU in the first place... start with junk and it doesn't get better as it ages.

 

[Leeea]

If they are brand name they will be fine.

If they are generic chinesium, they were crap to start with and aging them a few years is not going to help matters.

 

[VirtualLarry]

So what I would do is turn the system on, leave it idling in windows (not bios, so at windows power managed low power state) for a few hours instead of immediately going full bore into high load stress testing or gaming, etc.

in my opinion I would do is turn the system on, leave it idling in windows (not bios, so at windows power managed low power state) for a few hours instead of immediately going full bore into high load stress testing or gaming, etc.

O RLY?

 

[Fallen Kell]

Given that I have seen equipment with caps working fine that are 60 years old, and I have seen equipment with caps that are brand new which failed, it is really more about the manufacturing of the particular cap and what formula used for it. I would tend to agree that you should baby them for a bit on anything that was in storage for a long period of time. Give them a day or so of not doing much of anything before putting any real kind of stress on them.

You should know pretty quickly if they are still good since most electrolytic caps tend to fail spectacularly with a pop (though not always). Solid/ceramic caps will just fail to properly hold a charge and/or short open/closed (electrolytic caps can do this as well).

 

[mindless1]

I just experienced this reforming issue again today. Had a Corsair CX430 PSU, with failed 5VSB and 5V rail Samxon caps.

Rather than have to open it again sooner than later to replace the 12V rail caps too, elected to replace all major caps except the one HV side cap which usually outlasts the rest by multiple times.

Time flies! I didn't realize how old some of my cap stock is, some new (meaning unused, still in original packaging) Panasonic FM caps must've been at least 12 years old, stored in a mild, climate controlled environment. They were fresh stock from Digikey when originally purchased, I'd never bother buying unknown age stock from other than an electronics supply house for use in a KHz + frequency switchmode power application.

Put them in the PSU, connected to a light load (single digit amps on 5V & 12V rails). PSU ran for a split second and shut off. Protection circuit had kicked in, had to disconnect it and wait a few minutes for it to reset.

Next attempt, turn on PSU with no load. It turned on and ran, left running a few minutes and now will run with the light load, but am leaving it unloaded, then will let run with light load for a few hours, before increasing load.

This is my lazy way to do it. It does pose some risk that if there are internal shorts in the cap, enough to overheat it before it rebuilds the oxide layer, that it may vent or even explode. Either way, it's not going to Burn Your House Down (lol).

The rest of my new old stock caps, I'll make a jig and reform with a couple hundred K resistor in series to give them a few more years viable shelf life. Limiting current limits overheating and gives a better chance of good results. FYI this is a cap manufacturer approved/suggested thing to do, not outside their knowledge base or recommendations.

 

[killster1]

Would using them every couple years help prolong lifespan? Or will just leaving stuff in a box for many years be fine? Some stuff is just backup parts and such so I won't use it until something breaks.

get rid of your old stuff and get some new stuff every few years. no point in buying a shipping container full of psu's and powering them on every year so you can use them in your future builds in 30 years from now 😛

i have seen very few quality psu's catastrophically fail so just put your budget toward the psu THen the other parts and have fun!

 

[mindless1]

^ I see your point but "Get rid of your old stuff and get some new", has both a financial, and environmental impact.

You don't have to have a shipping container full, but full redundancy for any important system is a good idea, at least one of each component. I like my middle ground, maintain a limited # of both good/new spare(s), and repaired faulty ones to be demoted, spares for older, less valuable systems/uses.

Besides, infant mortality is a thing, as is increased points of failure/rate due to higher complexity or a less mature new design. Buying new doesn't provide rapid repair like maintaining spare(s) does. Then again it can be a good idea to buy the new widget while the old still works, so the old becomes the redundant replacement part, unless you're extremely limited in storage space.

I do this with just about everything I can, from automobiles to shoes. The automobiles do need exercised every now and then, but the shoes not so much. I don't have a spare kitchen sink. 😉

 

[killster1]

^ I see your point but "Get rid of your old stuff and get some new", has both a financial, and environmental impact.

You don't have to have a shipping container full, but full redundancy for any important system is a good idea, at least one of each component. I like my middle ground, maintain a limited # of both good/new spare(s), and repaired faulty ones to be demoted, spares for older, less valuable systems/uses.

Besides, infant mortality is a thing, as is increased points of failure/rate due to higher complexity or a less mature new design. Buying new doesn't provide rapid repair like maintaining spare(s) does. Then again it can be a good idea to buy the new widget while the old still works, so the old becomes the redundant replacement part, unless you're extremely limited in storage space.

I do this with just about everything I can, from automobiles to shoes. The automobiles do need exercised every now and then, but the shoes not so much. I don't have a spare kitchen sink. 😉

i suppose it depends what your systems do for how much you care. there is zero environmental impact for me to sell my spare hx850 and buy a new one when i need it (OK I LIED there is going to be the gasoline used to transport the used one and new one to and from me but i usually get packages so might not take any extra gas).

Now financially hmm keeping a old psu for 5 years while i wait to need it or buying one in 5 years when i do need it. how much will i save by saving this psu ((at perfect temp / humidity )) for 5 years? are pc's in 5 years going to use the same type of psu? do i really need this machine to last 10 years more? i used to be ALL about longevity and running parts for millions of years old servers etc. with everything new comes less power used, less heat pumping into my house on a 120f summer day. ((not like psu's tech has become crazy efficient compared to 10 years ago but a little)

Now i have multiple computers and zero critical tasks. i guess its similar to having multiple cars and having a spare tire on a full sized rim for when my tire goes flat etc. I dont want to go to the tire shop immediately so for convenience I just change to that tire and get the extra changed out later. But im not going to leave that spare tire sitting for 5 years i will swap it out every year etc to keep the rubber new (kinda like caps 😛 )

Shoes will also possibly become brittle like tires if keep them for 5 years 😛

how many important systems do you have? i guess you keep spares for less valuable systems/uses also..

 

[mindless1]

there is zero environmental impact for me to sell my spare hx850 and buy a new one when i need it

I don't wish to get into a long debate about it, but this is not true at all.

Buying new instead of keeping and repairing what you have, is the maximum environmental impact.

I am shaking my head that you can even make that statement.

It's still all about rejecting and decimating materials to a landfill and mining for more, instead of only using the materials needed to sustain and repair. The idea that someone else will use it, still comes back to an eventual early grave instead of longer use. How much less likely is the next owner, to repair instead of trashing it?

"Most" of a power supply can be reused, without even considering recycling materials, just fixing what is faulty. If you don't want to bother, I can accept that, but then you can't legitimately make your environmental claim because it's the opposite of the truth.

Maybe you make it up in other ways, but that doesn't change the reality of the situation.

It's a horrible waste to bury one's head in the sand and burden mankind with this waste then pretend it doesn't matter or is no different. It does matter, and it is different. This argument extends to far more than just power supplies, but is just as valid for them.

There are other areas of life where I take the same attitude you do, because I simply don't have the ability to make a difference on that front. I do what I can, and don't argue against others who found a better way...

 

[killster1]

I don't wish to get into a long debate about it, but this is not true at all.

Buying new instead of keeping and repairing what you have, is the maximum environmental impact.

I am shaking my head that you can even make that statement. It's absurd.

It's still all about rejecting and decimating materials to a landfill and mining for more, instead of only using the materials needed to sustain and repair.

"Most" of a power supply can be reused, without even considering recycling materials, just fixing what is faulty. If you don't want to bother, I can accept that, but then you can't legitimately make your environmental claim because it's the opposite of the truth.

Maybe you make it up in other ways, but that doesn't change the reality of the situation.

It's a horrible waste to bury one's head in the sand and burden mankind with this waste then pretend it doesn't matter or is no different. It does matter, and it is different.

There are other areas of life where I take the same attitude you do, because I simply don't have the ability to make a difference on that front. I do what I can, and don't argue against others who found a better way...

i didnt say i would throw the old one away, someone else will be using it but it will be sold by me to them. what is the difference instead of it being stored and possibly thrown away unused. My way possibly has less environmental impact. there is no guarantee it will ever be used by me if i save it.