The S-40B doesn't use a filter choke. It uses simple RC filtering.

The voltages are to be measured with the receiver set up as described
in the manual, that is without a signal being received. With a strong
signal present, the AVC voltage will increase the bias on the RF (6SG7)
and IF tubes (6SK7s) and the screen voltage will increase over the
no-signal condition. The B+ will increase a bit also. Another problem
is today's higher line voltages. Most of these old radios are designed
for 115 or 117 volts and when operated on 123-125 volts the B+ will be
15 or 20 volts higher than normal (115 VAC operation).
Best Regards,

Ed