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Using "new" old electrolytic caps in new circuits - Yay or nay?

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WyverntekGameRepairs:
Hello, I was working on a circuit at college a couple weeks ago using old Rubycon electrolytic capacitors (from around 1980, 1982... Pretty old), and it only just hit me now - How would age affect these capacitors?

So I have decided to ask all of you. When I received my capacitor design kit from a supplier a week ago, I noticed that it indicated that the components "expire" over time. I can see why - Age and the ambient environment temp, moisture levels, etc. can cause imperfections and decrease reliability in any component, especially electrolytic capacitors.
Knowing that age affects the performance and reliability of these capacitors, how good of an idea was it for me to use old electrolytics (even if they are Rubys) in a medium-voltage circuit? (The voltage being held by the caps was around 10VDC, and the caps were rated 1,000uF @ 24V). Another example is that I did a cap replacement on my Atari 2600 at my college campus as a small project. I replaced the main big cap on the switchboard (the one that filters the DC voltage in before it reaches the regulator) with an equivalent capacitor that was from around 1980 - it was in the original unopened Radioshack box packaging and everything - as well as a signal filtering cap on the switchboard with a axial leaded cap from around the late 1970's. Thinking about how even unused components are affected by time, I'm wondering if it is safe for me to be using these capacitors on my console or any other personal project I work on in the future? (Of course, I don't use New Old Stock parts for repairing other people's things, I only use new components.)

What do you think?

Nusa:
Hey, if it looks good and tests good and its for a personal project, nothing terrible about reusing parts. Especially if it's an expensive part to replace.

WyverntekGameRepairs:

--- Quote from: Nusa on December 22, 2019, 10:42:26 pm ---Hey, if it looks good and tests good and its for a personal project, nothing terrible about reusing parts. Especially if it's an expensive part to replace.

--- End quote ---

The Atari 2600's TIA chip comes to mind quite easily...
Anyway, I can see your point. I guess I'm just worried about old parts looking OK from the outside, but when they are put into working circuitry for the first time in decades (or ever, in terms of their life span) they end their short functioning lives with a loud *bang* and puff of smoke, and leave me dumbfounded as to what the hell just happened. Not that that has happened to me before, but it is a possibility of happening, and it is an eerie, disconcerting feeling. Like, I'm okay with using old components if I don't have new ones to replace it with (in personal projects only, of course!), but yet I sometimes have that eerie feeling that the life of the component could end loudly and unexpectedly after spending most of it's "life" in a parts bin for a few decades. :-//

mcovington:
I looked into this recently, reviewed the literature, made some tests, and came up with this:
http://www.covingtoninnovations.com/michael/blog/1910/index.html#x191006

I think 1980 is a bit old, but with Rubycon (high quality) it might be OK.  The guideline I ended up with is:

"My current practice is to freely use capacitors up to 10 years old, use them with caution up to 20 or 25 years old, and distrust those that are older. There is certainly no need to toss them when they're just 2 or 3 years old. ...

I expect people to write in and tell me I'm wrong. But I expect to be told I'm wrong in both directions (too cautious or not cautious enough), so it will balance out."

Capacitor manufacturing has improved recently.  Panasonic capacitors no longer have date codes.

james_s:
Capacitors (electrolytic) don't normally go bang, they just tend to increase their ESR and drift out of tolerance. They can also physically leak, so inspect the legs for signs of leakage and corrosion.

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