Testing Electrolytic cap's

Hi All,
Was wondering how to test electrolytic cap's before they are installed?

Thanks
Frank

I usually just do a cursory test for charge and discharge with an analog meter, setting the resistance to the point it will allow a relatively slow rise of the meter and a corresponding fall when the leads are reversed.

Frank, if they are new, I don't test them.  If they are vintage, listen to the sound when you drop them into an empty metal trash can, if they make noise when they hit the bottom, they are bad.
I don't have a cap tester but a VOM on the high resistance scale with + to + and - to - should show a dip to low resistance and slowly go up to the meg value as the cap charges from the VOM voltage.  Certainly not the best test and won't test HV leakage.
Jerry

Sorry 75, we were posting at the same time!

I do the same as 75X11! I also do the same as Jerry with Vintage caps!

Above is good advice.

Frank, unless you have "real" equipment, forget about it. You'd need a cap checker that has variable voltage output to test the dielectric strength for leakage and a high quality ESR meter to determine if dielectric heating may take place later on.

In my opinion, trying to "reform" caps with a trickle current supply is an absolute joke. Why would anyone trust a chemical composition that is several decades old that has high voltage across it and apart of something much greater (and sometimes very valuable)?

Stick with fresh, name brand caps and it's a non issue.

I, myself, only trust two manufacturers for restoration and custom projects/prototypes; Nichicon and Mashusita (Panasonic). I have had years of work to back those two up, and the companies have had decades of experience. "The proof is in the pudding".

I agree. Good advice here, Frank. Good luck.

WC

Thanks everyone.