Joerg said:
Hello Watson,
Nah. I have some 40+ year old radios where the electrolytic caps are
just fine. A couple times I actually did a resistor charge and leakage
test just to see. They were nearly as good as new.
Depends on a lot of factors including how long they have set without
being used, how long they have been used, how high a temp they have been
exposed to, etc. And of course how well they were made. The old timers
seem to be better made back then, and withstand the test of time better.
But the stuff being made today isn't as well made, IMHO. Smaller size,
les ofecerything, etc, means they don't last like they used to.
I just got thru replacing the main filter caps on two different HP PSes;
both were dead and gone. In one case the PS was 40+ yrs old, so it's
understandable. But 5 years is usually what they aim for. Hey, they're
full of juice, don'tcha know.
But sometimes when they had been in storage for decades they may have to
be "formatted" slowly to get them used to the job of "being a capacitor"
again.
That's reformed, as opposed to the original forming. And even so, you
may find that some of the juice has leaked, so you won't get the full
rated capacitance, but just a fraction.