Stock Electrolytic Capacitors

[patlaw]

I have hundreds of brand new electrolytic capacitors that have been in inventory for years. I wonder if I should pitch them. How often, if ever, do you flush your inventory? To my knowledge, I've never had a NOS cap fail, but I don't want there to be a first time. Every one I've checked has been good for value and ESR. Since I've started doing repairs again after a LONG hiatus, I find myself placing an order with Mouser for almost every repair. Having a good inventory may not be a good idea any more.

It's hard for me to throw anything away, particularly capacitors. Because the current ones are so much smaller than the old ones, getting a cap with the right lead spacing often requires ordering anyhow.

[Leo_Gnardo]

I have hundreds of brand new electrolytic capacitors that have been in inventory for years. I wonder if I should pitch them. How often, if ever, do you flush your inventory? To my knowledge, I've never had a NOS cap fail, but I don't want there to be a first time. Every one I've checked has been good for value and ESR. Since I've started doing repairs again after a LONG hiatus, I find myself placing an order with Mouser for almost every repair. Having a good inventory may not be a good idea any more.

It's hard for me to throw anything away, particularly capacitors. Because the current ones are so much smaller than the old ones, getting a cap with the right lead spacing often requires ordering anyhow.

Haven't had any problems with electrolytics made in say, the last 30 years. BUT I have a box of NOS "beer can" caps, 400 uF 450V dated 1966. Any takers? Ha, didn't think so. Those "beer cans" will find their way ta da dump ta da dump ta da dump dump dump one of these days. They're somewhere around here, buried under slightly less useless stuff.

[Chuck H]

Certainly small caps suffer the same age related problems as big caps, but...

Big caps, as in power supply filters, are typically run at or near their voltage rating, where small caps are often not. If a small cap is giving you 85% operation (old) instead of 97% (new) in, say, a cathode bypass circuit where a 25V cap is managing only 2V and less likely to fail, would you even notice if you hadn't heard it both ways?

I had a bunch of caps that never got used for the last ten to twenty years. And I don't mind "fitting" parts in place or using odd parts in repairs or builds. But I found myself questioning the viability of those caps such that I was buying new caps for each repair of project anyway. Realizing, then, that I was never going to actually use those caps I finally pitched them.

The trouble I see for repair guys is that ordering for each repair is clumsy and bungs turn around time. We had a thread on the subject not long ago where this aspect was the topic of discussion.

EDIT: I just found the thread and it looks like a consensus was never reached as to how old is too old for bench inventory. I, personally, would only trust NEW for high performance or operational spec applications like power supply and bias supply filters. I'm just not going to put a ten year old aluminum cap into a tube amp bias supply.

[patlaw]

EDIT: I just found the thread and it looks like a consensus was never reached as to how old is too old for bench inventory. I, personally, would only trust NEW for high performance or operational spec applications like power supply and bias supply filters. I'm just not going to put a ten year old aluminum cap into a tube amp bias supply.

My thoughts are that anything over 10uF should probably be pitched. Maybe I'll just put them in plastic bags and into a box that I put into storage such that my kids can throw them away. Hoarding is real.