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At what point should we throw out new capacitors that are "old"?

leesonic

leesonic

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Like the title says, at what point should we throw out new electrolytic capacitors that are "old"?

By this I mean, say you have a bag of caps that you bought a while ago for a project that never finished (or started). You bought them from a reputable source, like Mouser or Digikey, and they are a reputable brand (Nichicon, Rubicon, Panasonic etc.). The only snag is, the year code on the side is 2011, and it's now 2024.

Should these be thrown out? It's mostly small caps I'm talking about, less than $1 or £1 each. For the price of new ones, is it even worth using these? I guess you could use them somewhere non critical, like a phone stage if you never listen to vinyl, or the tone controls if you don't use them ever.

Sort of related, I know Nichicon has a four digit date code on the side. How do other manufacturers show this?
 
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2011 capacitor in 2024? In that hypothetical, I'd totally use them without question, assuming they've been stored within spec temperature (which, for most people's hobby spots, is totally not a problem).

If you're really worried, then measure them and toss them if they're out of spec (capacitance, ESR, and leakage current). But no need to send them to the landfill prematurely.
 
hold on to the older ones for those things that are beyond economical repair .
i do suppose if they look and test ok then they likely are .
 
From what I have heard, if they are babied for a minute or so they will form up and be fine. Pushing a dormant cap to the max instantly can lead to a failure, once in a while, pop. Same goes with a receiver that has sat unused for a long time, it will appreciate being powered up under a low wattage dimbulb for a few minutes before use. When I install caps I'm always using a dbt, so no extra work.
 
Can solid state amps be brought up slowly on a variac? Or would the protection circuits go crazy.
I ask because i plan on replacing the big caps on my McIntosh 7270, the new caps are not that old, but just wondering if that would be necessary.
 
Yes a variac can be used, it just won't come out of protection until there is enough voltage to operate the circuit. But if you are replacing parts in general a dbt is the method of detecting a short. If your caps in question are a year or two old, there really should not be an issue with re-forming.
 
petehall347 said:
hold on to the older ones for those things that are beyond economical repair .
i do suppose if they look and test ok then they likely are .
Click to expand...
I do that. Keep old caps that I've pulled that still test good. Then use them in various things I repair that just aren't worth much to begin with.
 
Thanks for asking. I too have a mixed bag of caps (about the same age), and had wondered that myself.
 
If the leads turn green and fall off from corrosion, I’d pitch em. If they look new just use em.
 
The original main filter caps in my Onkyo M-508 amp (bought new in 1986) went bad in 2000, and I replaced them with Nichicon caps with 1995 date code- those lasted until 2008, and were replaced again with newer Nichicon caps made in 1998- the last ones available as Onkyo stopped selling caps for the 504 & 508 in 1998 (they have a weird four pin connection to the circuit board). The amp was seldom used after this second recap and they started leaking again in 2022. For the third recap I used brand new Cornell Dubilier (CDM) caps--hopefully this set will last longer than I do.
 
The mostly AC/DC radios I work on get all the caps replaced. Sometimes these 80 year old caps still test "good", I still don't trust them. The box I throw bad parts into is full, time to toss them.

Mike

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