Found a hidden stash of old capacitors in a basement cleanout

I was clearing out a customer's basement last week in St. Paul and came across a box of vintage capacitors from the 80s, still sealed in their original packaging. Tested a few on my meter and surprisingly they held charge better than I expected, which got me thinking about shelf life claims. Anybody else ever stumbled across old components that still worked fine, or am I just lucky?

3 comments

3 Comments

markh8529d ago

That test with the meter is the real tell. I found a box of Panasonic FC series caps from 1994 in my uncle's garage a few years back, and they all read within 10% of their rated values. The dielectric aging thing is overblown for high quality parts stored in a stable environment. What kind of voltage and temperature conditions did you test them under though? If you just slapped them on a meter at room temp, that gives you one picture, but the real test is ESR at full rated voltage or under some heat. Were they aluminum electrolytics or something else like film caps?

violar3529d ago

Well, and here I thought I was being clever just checking if they still held a charge, like some kind of caveman testing a battery by licking it. I actually just used a cheap digital multimeter at room temp, no fancy ESR meter or anything like that. It was a mixed bag, mostly aluminum electrolytics from the late 80s and early 90s, a few Panasonics and Nichicons. You're right, the real test is under load and with heat, I imagine they'd start to show their age then. My garage is pretty stable, but not climate controlled, so who knows how many summers they sweated through. I guess my little test proves they're not dead, but they might be pretty tired under real work.

murphy.mason29d ago

Blew up a friend's power supply testing some old caps from his dad's workshop once... They were these big blue Spragues from the 70s, looked perfect on the meter at room temp. He hooked one up in a simple filter circuit and it started humming real loud before letting the magic smoke out after about 30 seconds under load. His whole basement smelled like burnt electronics for a week. So yeah, your meter test might say they're fine, but heat and voltage bring out the truth real quick.