Longevity of electrolytic caps in non-use/in-storage gear - Page 1
Forum section: electronics / projects

author: 13hm13
author_rank: Frequent Contributor
timestamp: April 12, 2014, 03:20:46 pm
content: Say I have a mid-range Yamaha audio integrated amplifier, which uses decent (Panasonic FC) but not top-end (Panasonic FM) electrolytic caps. I use the Yamaha for a 1 year, typical non-abused use, about 2hrs/day (so, ~720 hrs total use). The amp is powered up for use and powered down after use (note: on/off may be more stress than always-on). Then I get a new amp and put the old Yamaha in storage.Assume room temp use/storage cond. always.W/o ESR-meter (or other) testing, how long will the old Yamaha's electro caps last in storage? E.g., not leak or "vent out"? Or should I be worried about other components in the device "rotting out" before caps?P.S. Another way to think about it is when pertaining to new old-stock components or gear. E.g., say I buy sealed (in-box) 20-year-old PC PSU or motherboard on eBay.

author: SeanB
author_rank: Super Contributor
timestamp: April 12, 2014, 03:35:07 pm
content: Should do 10 years if good quality, but depending on the batch, parts used and process quality ( QC went out for lunch and forgot to check that the parts were genuine and not stuff out of a sweatshop) they might last 20 years or longer. Lifetime is temperature and voltage dependant, and not necessarily linear. Same batches had a poor life due to being formulated incorrectly, but lasted out the warranty.

author: 13hm13
author_rank: Frequent Contributor
timestamp: April 13, 2014, 02:19:43 am
content: I've heard from some techs that the large/main rectifier caps are the longest lasting if not abused.Just as an anecdote .... my Tek 465 (1976 vintage) o'scope is works well ... it has never been re-capped.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 13, 2014, 02:38:14 am
content: I had to recap my 475; got a solid 5 years or so out of it before things got too nasty to deal with (ripple in the deflection amps, etc.).We had a thread recently discussing this...Tim

author: calexanian
author_rank: Super Contributor
timestamp: April 13, 2014, 05:25:42 am
content: Temp seems to be the biggest factor apart from quality control related issues. I generally speaking once a cap is formed in use the clock starts and EVERyTHiNG is a factor. Ideally if you are not using a piece of equipment with lots of electos in it you want to power it up and let it soak for a while. Use it a bit from time to time. This does actually increase cap life. What you don't want to do is use something for a few years, then store it for a decade, Turn it on , let it get really hot, and eat itself.Additionally for example a 105 deg cap used daily but never sees over 50Deg will most likely last many many more hours than stated in the lit. I give you a Tektronix TAS220 scope of mine for Example. Gets turned on at 8 am every day and turned off at 5 pm, and its been doing it for many years no prob. And I expect it to go on doing it another 10 years min. The box never even gets warm to the touch. I am sure in the lit for the caps in there they are like 3000 hrs or something like that. They saw that in no time, but that spec is at an elevated temp and ripple current the thing will just never see.

author: 13hm13
author_rank: Frequent Contributor
timestamp: April 13, 2014, 07:27:29 am
content: Quote from: T3sl4co1l on April 13, 2014, 02:38:14 amDefinitely interested in the issue of vintage o'scope re-capping. Gotta link for that discussion?

author: 13hm13
author_rank: Frequent Contributor
timestamp: April 13, 2014, 07:39:43 am
content: We're going OT a bit here by discussing in-use caps (but that's okay!!)Quote from: calexanian on April 13, 2014, 05:25:42 amAgreed (about temp and orig. QC) ... additionally, I think very clean/filtered power makes a diff. I use a DIY inductor-based approach often used in high-end A/V installation (line conditioners, power filters). And then I cascade from there with off-the-shelf devices like Tripp-Lites, etc. I've thought about getting a used industrial-grade inverter on eBay. I know certain "high-end" audio and video set-ups use them (e.g., by PS Audio, etc).Very $$, tho;For computers, a very good PSU helps further clean up (condition) power for the motherboard and other, powered devices.

author: brevor
author_rank: Newbie
timestamp: April 14, 2014, 01:43:26 am
content: I have some unused 2200 uF electrolytics that were manufactured around 1980, so they are not the newer low ESR caps. Anyway I pulled one out to use in a repair around 2007, a check with a capacitance meter showed no loss of capacitance. Repair worked fine.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 14, 2014, 02:14:09 am
content: The caps in an audio amplifier won't see much load unless you're playing it really loud, so they're most likely "as good as new" to begin with. A possible failure mechanism is electrolytics deforming due to lack of use, but modern caps shouldn't have that problem and it takes many years to show up anyways, so you can just power it on for a few hours every year (hint: use it in a Christmas display or something!) as a preventative measure.That said, I have yet to come across a cap that failed from just being in storage. The slow charging process before putting them back in use is really more of a precaution.

author: calexanian
author_rank: Super Contributor
timestamp: April 14, 2014, 05:02:35 am
content: Quote from: brevor on April 14, 2014, 01:43:26 amThis is not uncommon. You have to make sure they form properly and stabilize then retest. If they have just been sitting dry cool and happy in their box or on their spool or in the bag they have had no reason to go bad apart from leaking electrolyte or some other chemical degradation.

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: April 14, 2014, 05:14:47 am
content: Quote from: 13hm13 on April 13, 2014, 07:27:29 amThere have been more than a few, sorry I don't have the links at hand. I notice because as a beginner I find the repair threads to be like mini-mysteries and a lot can be learned from some of the electron sleuths that visit here.Look for the scope repair threads mostly under "Test Equipment" I think.

author: 13hm13
author_rank: Frequent Contributor
timestamp: April 14, 2014, 11:12:39 am
content: It would seem as electro caps would benefit from modern, computer-controlled (= tight) production/assembly lines. This has certainly helped with circuit PCB and ICs.Not sure electro caps are more "hands-on" manuf.?Why exactly are, e.g, Panasonic and Nichicon caps better than cheapies from China? Q.C., materials quality, etc...

author: calexanian
author_rank: Super Contributor
timestamp: April 14, 2014, 05:10:06 pm
content: The chemistries of the electrolyte is closely held secrets for each company. Panasonic, nichicon, chemicon, IC, and other high mark caps all have many many decades of experience. That's where the quality really kicks in.

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: April 14, 2014, 05:41:58 pm
content: Quote from: calexanian on April 14, 2014, 05:10:06 pmBut how much of a secret can it be? You cut it open and run a chemical analysis and voila.I think the differences are simply about quality and choices and manufacturing efficiencies.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: April 14, 2014, 05:53:16 pm
content: It may come down to initial build quality. Aluminum electrolytics are incredibly sensitive to certain types of contamination, chlorides in particular. A fingerprint during assembly is all it takes to shorten the life dramatically. Ditto any chlorinated solvents used in PCB manufacture that get past the seal. Raw material quality matters. After a lot of measurements and servicing old audio equipment I can say with some confidence that there's no rule of thumb that will help you. Some caps are completely healthy many decades later, stored or not, others die an early death. This seems true of even the best manufacturers, though I'd never buy a cap from other than the big players. I've got some related into and opinions here-http://conradhoffman.com/capchecktut.htmBTW, I'm working on an old Yamaha receiver right now that I found at the dump. It has some issues, but so far caps don't seem to be one of them. For all the fears people seem to have about caps, they're generally quite reliable decades after manufacture. Cooked in tube equipment, they sometimes don't do quite so well.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 15, 2014, 01:34:34 am
content: Quote from: Conrad Hoffman on April 14, 2014, 05:53:16 pmYeah, the ones that weren't thrown out decades ago from early failures. Call it, extended burn-in testingTim

author: David Hess
author_rank: Super Contributor
timestamp: April 15, 2014, 10:50:09 am
content: Experience with PC power supplies and consumer equipment over the past few years has led me to suspect that the when the manufacturers do not screw up, they are precisely engineering the filter capacitors to fail just out of warranty.

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: April 15, 2014, 03:14:12 pm
content: Quote from: David Hess on April 15, 2014, 10:50:09 amYes, you probably know this already, the term is "planned obsolescence". They engineer the life (or death) cycle into the product.I'm most familiar with iMac G5 failure. Another term you may or may not have heard is "plausible deniability".Apple got plausible deniability by pointing at the caps and saying "see the cap manufacturer made bad caps". Then Apple don't look bad and comes out looking clean. I'll let you decide if Apple knowingly used the bad caps.Plus caps have a reputation for usually being the culprit for failures in electronics so as far as I know there were no lawsuits.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: April 15, 2014, 03:47:29 pm
content: I don't think it's so much planned obsolescence, as buying the cheapest thing they can possible get their hands on. There also seems to be a trade off envelope. You can't get long life, low esr, small size, long shelf life, low cost and low DC leakage all at the same time. If you concentrate too much on everything but life, you tend to get short life.

author: David Hess
author_rank: Super Contributor
timestamp: April 15, 2014, 04:30:36 pm
content: Quote from: GiskardReventlov on April 15, 2014, 03:14:12 pmI think the change which allowed this though is detailed specifications on capacitor lifetime versus ripple current and temperature in applications where this matters. Previously without this information, designs had to be overbuilt.It is one thing to engineer for the design life of a product but it is unusual to have a part with such a defined operating life. When manufacturers started using non-volatile memory backed up with lithium batteries, they did not adjust the current draw so the memory would fail just out of warranty. I suspect a similar tuning goes on with some products that use non-replaceable rechargeable lithium-polymer batteries.QuoteDell, Samsung, and Mitsubishi have been sued over capacitor failures.

author: GiskardReventlov
author_rank: Frequent Contributor
timestamp: April 15, 2014, 05:39:03 pm
content: Quote from: David Hess on April 15, 2014, 04:30:36 pmI was only speaking of apple. Most people upgraded to a new mac. Some people repaired them. Some customers were not too mad about it and gave them a good excuse to upgrade.