Welcome to Solid State Guitar Amp Forum | DIY Guitar Amplifiers. Please login or sign up.

November 29, 2022, 08:24:06 PM

Login with username, password and session length

Recent Posts

 

Do Electrolytic Caps Age ?

Started by Tassieviking, June 12, 2022, 03:57:08 AM

Previous topic - Next topic

Tassieviking

G'day all
So my father died a week ago,and my brother 3 years ago and mum 5 years ago.
Going through all the stuff in my fathers house I have found lots of Electrolytic caps,
Some are around 6800uF 65V, 2200uF 80V, etc. I know these used to be my brothers but he moved overseas about 20 years ago.
Will they still be ok to use in new amp builds or should I scrap them, they have never been used.
There are also bags full of 1uF, 10uf, 22uF etc, never used and heaps of WIMA box caps.
I have to ship them over 2000km back to my place so I only want to keep good *s!!t*.
???
There are no stupid questions.
There are only stupid mistakes.

dimkasta

Yes electrolytic caps definitely age. But it's hard to say how much life exactly you can expect from them. It depends both on the usage, but also on the storage conditions and their quality. 20+ years is the point where I would start worrying. A quick way to get rid of duds is to see if their case is bulging or leaking.

A quick sample from the internet



I would still worry though. Even if they have no visual problems, they can still be duds. A safer way is to test them with a multimeter or even better an LCR or ESR meter.

You mention wimas. These are probably film and these age in a much much much slower rate. The most usual problem with them is oxidization of the wires (which can be solved with some sandpaper)

mandu

I had a pair of new 6800mf/80 volts caps in shelf for 10 years. With capacitance meter both measured good above 6800 mf. To clear doubt I connected a 40 volts DC supply and left for 30 minutes. The capacitors became very hot and I have to throw them away.
Either the capacitor becomes dry (lower capacitance) or have lower dielectrics (high leakage current).
You can connect a DC power supply to it and check if they survive as I did.
If the physical look is bulged, then throw them away.
Regards. 

Tassieviking

Thanks guys for the answers, I think I will not keep the Electrolytic caps since I don't know the age of them.
Better be safe then sorry.
There are no stupid questions.
There are only stupid mistakes.

mandu

Quote from: Tassieviking on June 19, 2022, 08:58:36 AMThanks guys for the answers, I think I will not keep the Electrolytic caps since I don't know the age of them.
Better be safe then sorry.

I would suggest you experiment with those old electrolytic capacitors before throwing out to learn something and acquire some knowledge out of it. Regards.

g1

Quote from: mandu on June 19, 2022, 10:23:46 AMI would suggest you experiment with those old electrolytic capacitors before throwing out to learn something and acquire some knowledge out of it. Regards.
Yes this is a good idea.  And running the charger with a limiter lamp will avoid the overheating that you experienced, and sometimes bring them back to life if you are patient.