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

I'll second that! I've found that, given a house line voltage of from
120-127 volts, many of my older receivers used to get very hot. I
installed a 7A Variac on the line dedicated to the BA'a and set it for
110v. No more problems.. at all.

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

Thanks for all the input. We found a suspect resistor in the B+, just at
the filter capacitor. It's a 1500 ohm, 10 watt unit that now measures
1400 ohms. We'll try a higher value (say 1800 ohms) based on the
"revised" house line input voltage to bring the overall voltage down a tad.

John

KE0GG

K3HVG wrote:
I'll second that! I've found that, given a house line voltage of from
120-127 volts, many of my older receivers used to get very hot. I
installed a 7A Variac on the line dedicated to the BA'a and set it for
110v. No more problems.. at all.

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

Thanks for all the input. We found a suspect resistor in the B+, just at
the filter capacitor. It's a 1500 ohm, 10 watt unit that now measures
1400 ohms. We'll try a higher value (say 1800 ohms) based on the
"revised" house line input voltage to bring the overall voltage down a tad.

John

KE0GG

K3HVG wrote:
I'll second that! I've found that, given a house line voltage of from
120-127 volts, many of my older receivers used to get very hot. I
installed a 7A Variac on the line dedicated to the BA'a and set it for
110v. No more problems.. at all.

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

I'll second that! I've found that, given a house line voltage of from
120-127 volts, many of my older receivers used to get very hot. I
installed a 7A Variac on the line dedicated to the BA'a and set it for
110v. No more problems.. at all.

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