I am rebuilding a model 4D Detrola. Does anyone know what the plate and screen voltages should be? I had to change the transformer and now the B+ is 220VDC.

Hi Joe

220 volts between chassis & pin #2 on your 47 tube is reasonable. You could have up to 250 here.

http://www.nostalgiaair.org/PagesByModel/039/M0004039.pdf

Norm

:I am rebuilding a model 4D Detrola. Does anyone know what the plate and screen voltages should be? I had to change the transformer and now the B+ is 220VDC.
:

Thanks Norm
This radio uses a 78 for the RF amp.I had to use a 12K resistor from B+ to plate and a 150 ohm resistor from
from cathode to ground to get it to bias. I also had to reduce the volume control from 8K to 2K. My gate voltage is now -.8VDC. It is working but the output is still weak. Do you know what value of inductance the coils should be?
Thank you
Joe
:Hi Joe
:
: 220 volts between chassis & pin #2 on your 47 tube is reasonable. You could have up to 250 here.
:
:http://www.nostalgiaair.org/PagesByModel/039/M0004039.pdf
:
:Norm
:
::I am rebuilding a model 4D Detrola. Does anyone know what the plate and screen voltages should be? I had to change the transformer and now the B+ is 220VDC.
::