[Boatanchors] Old Electrolytics Any Good?

[fkamp at comcast.net]

Jamesnf at aol.com wrote:
> 
> I stumbled across a box of 1000Mfd @ 450v electrolytics on a shelf in the
> basement.  I think I brought these home from a hamfest 20 years ago, maybe
> longer.  Is there any possibility these could still be usable after all this time?
> Or should I just deposit them in the trash?
> 

Try reforming the dielectric film if they look like they have not leaked
or are otherwise damaged.  Start at a low voltage, around 50vdc or so,
use a series resistor, 1k should do, then see if they take a charge
without problem.  If so increase the voltage to 100vdc and let them rest
at that voltage for an hour or so.  Keep increasing voltage but I would
not go higher than 425vdc.

If the resistor did not burn up and the caps did not explode, they are
probably okay to use.

Or, the simpler solution is to just trash them and buy new.  It all
depends on how badly you need them and how much money you are willing to
spend.

Regards,
Frank Kamp
K5DKZ