03-13-2015, 07:00 AM
Ron, check the voltage drop across the field coil, as I believe this is where the bias voltage for the output tube is developed. Then there is a voltage divider which should drop the negative voltage to -20 to -25 V at the 41 grid
measured to ground.
If the bias is correct and the plate and screen voltage is within limits, then you are probably ok. I have seen 6K6's with glowing screen wires for apparently no reason and they seemed to operate this way normally.
How does your line voltage compare to the radio's power spec? Perhaps this is contributing to your high DC voltages. As you mentioned previously, this radio is probably a prototype and the power transformer may not be the same as was used in final production.
measured to ground.
If the bias is correct and the plate and screen voltage is within limits, then you are probably ok. I have seen 6K6's with glowing screen wires for apparently no reason and they seemed to operate this way normally.
How does your line voltage compare to the radio's power spec? Perhaps this is contributing to your high DC voltages. As you mentioned previously, this radio is probably a prototype and the power transformer may not be the same as was used in final production.
