[Eliot Ness]

While I have an ESR meter I don't use it at all on old radios because of the before-mentioned limitations. I do have an older Heathkit and Jackson capacitor tester that will apply up to 500 volts that makes them useful for testing leakage on the types of caps we use in old radios.

While I always replace all the paper and electrolytic caps when I work on a set I like to check them first for a couple of reasons. One, I have a pretty good stock of quality, but older ceramic & epoxy caps I've picked up at hamfests and the like over the years so I just like to make sure my stock is still good. The second reason is the caps we get today are almost all coming from China and I don't trust their quality control. While none of my older stock has failed a test I have had a couple of the "Chinese specials" test a bit funky.

There are a lot of nice older capacitor testers that will suit our needs, but my personal favorite is a Jackson 650A, mainly because after a rebuild it is pretty accurate, easy to use, and it will test leakage up to 500 volts.