expected lifespan of capacitors

[krunchy]

capacitor lifespan

What is the lifespan of ceramic, polyester, monolithic, tantalum and electrolytic capacitors? I'm restoring a MemoryMoog synthesizer built in 1983. Should I replace all the capacitors or only the electrolytic?

 

[Jack// ani]

capacitor lifespan

After so long electrolytic capacitors will be dead for sure, replace them first and see if you can get it working.

Tantalum being the most reliable one stand better chances of still being alive.

 

[IanP]

Re: capacitor lifespan

I would worry only about the electrolytic capacitors and their limited life-span ..
Over several years the dielectric may deteriorate beyond regeneration, resulting in a high leakage current, or the electrolyte will eventually dry away, reducing the capacity by several orders of magnitude ..
And the above is the reason that people – like yourself - who restore antique radios will often be faced with the need to replace all electrolytic capacitors ..

Rgds,
IanP

 

[FvM]

Re: capacitor lifespan

After so long electrolytic capacitors will be dead for sure.

No. You can expect an elevated failure rate, particlarly if the capacitors have been operated a higher temperatures.
I have number of devices that are considerably older, both consumer and professional electronics, incorporating
many electrolytic capacitors, and they are still working.

Some devices have however known weaknesses, e.g. capacitors operated with a high ripple current or of apparently
bad design, they should be replaced as a preventive maintenance action.

 

[karesz]

capacitor lifespan

Yes,
with typical conditions the most passives has very long lifetime!
Especially tantals-I have lot of old examplares of (solid) ones from IBM computers, their are yet at 30-35 years old, OK the past 20 years not worked, but are very good functioning(I dont know some over ESR)+ values are in ca. 5%-they are nominally 10%....
In all cases are surly elkos the most sensitive, in spite of it we can meat lot of old (not only military) tube TX/RX, Equipments) their are after 20-50 years OK....
This is most a question of right component dimensioning
K.

 

[biff44]

Ceramic caps should last forever.

Like they said, electrolytic types are probably shot.

I have heard that you can "rejuvinate" old electrolytics, but I would just replace them with nice new caps.

Any series cap that is blocking DC from one stage to another should probably be replaced anyway, as if there are any defects, they will give shot noise to the signal. Get some nice new ceramic caps and away you go.