In response to someone “testing a box of old condensers”, I acquired part of a member’s collection to sell for his widow. In the mix was a box of NOS and used condensers. There must have been upwards of a couple hundred. I tested all of them using a Heathkit C-2 condenser tester. When tested at 300V, three of them were good. One was a brand new part, the other two were original condensers from a Johnson A.
If you are serious about testing condensers, I suggest finding a Heathkit C-2 or C-3 condenser tester and recapping it. They can tell capacitance as well as leakage at high voltage, and can also be used as an ohm meter. They are a bit expensive; about $75 to $100 on Ebay, but you might find one locally at a flea market. Recapping will run about $20 or so for parts. But the cool factor with the magic eye tube is worth it if you’re going to get some use out of it.
This is what the C-3 looks like; the C-2 is the old style tan with red lettering. The C-2 is usually a little cheaper than the C-3. Circuit is pretty simple.
