"William Sommerwerck" wrote in message
. ..
Hmmm... This is a totally unfamiliar circuit, so I'll limit my ignorant
comments to the following.

Based on what I can figure out, the plate current is 1mA. That should put
the cathode voltage at 60V, not 70V -- which still seems rather high.

I assume you've checked the obvious stuff like the resistor values.



Indeed I have. In fact, every component but the tube itself in the circuit
is new, as I had to rebuild the power supply, first audio, driver, output,
detector and AGC circuits back to factory design. This one's a puzzle for
me. The voltages on that stage are strange. Plate voltage is quite high,
IIRC, around 240 volts, and the grid is at essentially zero. It's all
supposed to be a part of that squelch circuit, I'm sure.. perhaps it's
staying in the squelched mode for some reason.