04-27-2018, 05:57 PM
The original caps might measure OK with a capacitance meter (although in my experience this is rare). The larger concern is their leakage at operating voltage.
Most modern multimeter style capacitor testers do not do this. I have a Sencore meter than is able to test for leakage near the rated voltage. I got it mostly it out of curiosity - and I've found that almost without exception the paper caps I've measure in these old sets are very leaky and unreliable. Mica caps are usually still in good shape (note that on occasion you might find bakelite blocks that contain mica caps - these are typically ~120pF - but just as often paper caps were used for the same value).
If you want the radio to work as it was originally you will want to replace all of the capacitors. The original capacitors are many many decades past their intended lifetimes.
Most modern multimeter style capacitor testers do not do this. I have a Sencore meter than is able to test for leakage near the rated voltage. I got it mostly it out of curiosity - and I've found that almost without exception the paper caps I've measure in these old sets are very leaky and unreliable. Mica caps are usually still in good shape (note that on occasion you might find bakelite blocks that contain mica caps - these are typically ~120pF - but just as often paper caps were used for the same value).
If you want the radio to work as it was originally you will want to replace all of the capacitors. The original capacitors are many many decades past their intended lifetimes.
