electronics devices 1990 store for not failed electrolytic capacitors

[tiago1986]

I have old electronic devices from 1990 saved What is your recommendation for the storage period without the electrolytic capacitors failing due to disuse? I asked manufacturers and they didn't answer or they were confused

[David Hess]

Smaller aluminum electrolytic capacitors can be worn out without use in 10 to 20 years.

[james_s]

The really bad ones are the surface mount electrolytic type, they leak and make a huge mess. Regular through hole electrolytics are usually fine in storage.

[David Hess]

The really bad ones are the surface mount electrolytic type, they leak and make a huge mess. Regular through hole electrolytics are usually fine in storage.

Even in storage they slowly dry out.  This is a problem with small parts because they have more leakage for a given volume.  A large part might leak twice as fast but has 8 times as much electrolyte.

But the timescale is decades, or at least more than 10 years.

[Stray Electron]

  Probably the best way to store anything with electrolytics in it for a long time would be to power them up occasionally to prevent the electrolytic caps from deforming.  (Once every six months?) Other than that, keep it in a DRY environment and as cool (non-condensation) temperature as possible. Lower temperatures will slow down any chemical reactions that could degrade the caps. It would probably help if you could store it in a vacuum or in some sort of inert gas or nitrogen but that's probably not practical. Oh, and put desiccant in the container too, and take out any batteries that are in the equipment!

   I recently bought a big military automotive electrical system tester that has been in storage since it was refurbished (by the GOV) in 1978. I don't know how it was stored originally but it still has bags of desiccant still inside of the aluminium shipping/storage case and it is in excellent condition.

[tiago1986]

I use an air dehumidifier in my room with a compressor and I keep it working morning and afternoon and I turn it off at night and at dawn the humidity is at most 70% immediately I turn on the dehumidifier and after a few hours the humidity goes to 55% the temperature varies between 30-33 ºC, dehumidifier many noise night

[David Hess]

The reforming issue after long disuse is more applicable to high voltage aluminum electrolytics which were found in tube circuits where even a small reforming current could result in considerable power dissipation.  I do not know that it has ever been an issue at line voltages and lower.

[rsjsouza]

In my anecdotal experience, the smaller the capacitor the higher the chance it fails and leaks. The earlier electrolytic SMD capacitors were particularly leaky, but I blame on the lower margins of error due to miniaturization: 1980s/90s laptops, personal organizers, calculators and other high density electronics all suffered this in one way or another.

The oldest equipments I have with electrolytic capacitors are a 1946 Philips radio and a Power Designs power supply (last cal was in 1969). While the radio has its main capacitor most probably dried up (due for a renovation), the power supply is still in top shape - the large GE "computer grade" capacitor is still performing very well. Other 1980s pieces of gear are still performing good such as a HP5300B/5308A, HP3312A, 3314A and a BK Precision 3300. On the other hand, all my older Flukes (8020A, 8060A, 8062A) had at least one or two tiny capacitors out of spec (although not leaked).

However, the size/leaky equation has been changing in the last decade or two with the popularity of switching converters/power supplies: the larger tank capacitors in the DC outputs tend to give up a lot faster due to the switching ripple - not to be confused with the high voltage tank capacitors of the primary voltage, which tend to have a long life. Also, the ambient temperature is a contributing factor: although the old vacuum tube circuits were bad, the solid state usually was well ventilated until you get to the high densities of plugpacks and miniaturized electronics.

A good LCR meter is key to evaluate all this - I highly recommend for anyone that does repairs.

[tiago1986]

I have read a lot about electrolytic capacitors and I learned that it is necessary to use them for electrolytic capacitors not to have failures but I do not know if it is to use the electronic device every month or another time interval and I have 1990 electronic devices with capacitors used electrolytics, i have crt tvs, videogames, and other electronics

[BrokenYugo]

Only ones I'd bother going after preemptively in solid state stuff are the old SMD electrolytics just because they tend to fail in a destructive manner. I have some cheap consumer grade stuff from ~1980 onwards that still runs fine on original parts. When I did a recap job on my NES the only bad cap I found was the one causing problems. Based on age I replaced all electrolytics in my ~50 year old Heathkit oscilloscope, only some of the high voltage electrolytics run near/at their max voltage ratings tested a little iffy, and they were still working in circuit, all the low voltage caps were still of good ESR and in spec.

Don't leave anything plugged in and use it all occasionally, wheel out the parts cannon only when you need to.

[tiago1986]

is it necessary to use the electronics of 1990 every month for the electrolytic capacitors to have no problems?

[rsjsouza]

I never did and have working equipment of 1980s and 1990s.

[tiago1986]

Do you have any concrete information for the storage time of electrolytic capacitors in electronic circuits and manufactured since 1990? 1 month, 1 year, 2 years etc

I don't mean new and spare electrolytic capacitors?

[rsjsouza]

I don't think any study was ever done on this, mostly due to the wide variability of the boundary conditions: how many hours the equipment was used, what temperature and humidity it was subjected, how much voltage ripple its design allowed, and so on.

If a manufacturer did a study, there's always the unrestng feel they can be excessively cautious so it does not hamper sales.

I tend to store equipment that is infrequently used in closed boxes with de-humidifier bags made by me (I can buy silica-gel in bags) but you have to be careful with other parts as well, which can suffer from extreme low humidity - leather and radio dial strings being the biggest offenders.

[BrokenYugo]

You're overthinking this, there's no magic formula to make this stuff last forever, best practices have been explained (power off, cool dry place, plug in and power up occasionally). Odds are what you're asking has never been formally studied, aside from perhaps military/aerospace grade parts why would it be? There is little commercial value in knowing how exactly to push something well beyond it's designed service life, that sort of thing is firmly in the realm of the hobbyist. I guess you could ask some of the computer museums with more operational collections of consumer grade stuff their practices (Living Computer Museum in Seattle comes to mind), but they probably won't tell you anything different. I've been to that museum and it seemed to be kept like any other office type building, air conditioned to be cool and dry.

I believe SNES falls under that umbrella of early surface mount caps that like to leak and eat the board, no storage practice will prevent it from happening eventually, the only options are run to failure or "shotgun" it with all new high quality caps.

[David Hess]

You're overthinking this, there's no magic formula to make this stuff last forever, best practices have been explained (power off, cool dry place, plug in and power up occasionally).

Also on the necessary but not sufficient list:

4. Do not use non-hermetic capacitors which rely on a liquid electrolyte.

[tiago1986]

humidity between 40 and 70% in period 24h does not harm plastic and rubber of electronics? I use dehumidifier and it keeps this humidity rate

i have crt tvs and snes ad ps2 slim 90000 consoles