Frank Dresser wrote:
"geojunkie" wrote in message
om...


It's easy to figure how much capacitor leakage would cause an excessive
grid voltage, a reduced screen voltage or plate voltage. It's a simple
ohm's law problem. Don't forget the power leaky bypass capacitors have
to dissapate. Cathode bypasses can get very leaky before causing
problems.

But I'd be surprised if there are any 40+ year old paper caps around
that can meet a fairly loose throw away standard now. Say 1 microamp
per microfarad at it's rated voltage.

What year was your SX 101 made? Mylar caps started showing up around
1960. Even my SW 500 (S 120) had several good quality mylar C-D Black
Cats.

Also, there was an early 60s version of the Sprague Black Beauty which
was paper-mylar rather than paper-oil. The paper-mylar cap was quite
reliable.

Frank Dresser



Here's an excellent way to determine if paper caps should be replaced.
Count the number of caps in the radio and divide by the number of times
you want to go in and re-troubleshoot. If the quotient is equal to or
less than the original number of caps then they should be replaced.

Hope this helps,
Bill