[MrFixr55]

Hi Roy,

Yeah, I am scratching my head here. I assume that sensitivity and volume for this radio is low. I also assume that you have the radio hooked up to a long wire antenna and ground.

OK, for a little science:

Per the RCA receiving Tube Manual, the "Screen" Voltage for both tubes should be around 100V for a Plate voltage of 250V. The 6A8 Screen current at this voltage should be 2.7 mA. The Screen current for a 6K7 at this voltage is 1.7 mA for a total of 4.4 mA. Now if E=IR (Voltage = Current X Resistance) per Ohm's Law,
0.0044 Amp X 22,000 Ohm = 96.8 V voltage drop across the resistor R4. If the resistor is supplied with about 200V from the voltage divider, then the screen voltages should be about 103V

OK, with both tubes in, measure from Chassis ground to the side of R4 that connects to the Voltage divider junction between R14 and R15. Record that voltage. I expect that voltage to be about 200V +/- 20V. If significantly lower, then this must be investigated. Next, measure the voltage across R4. Record that voltage. I am expecting that you are going about 140V across that resistor instead of the 100V that I think that you should get if everything is working correctly.

Therefore, either there is something wrong with one of the tubes or something wrong with the biasing of these tubes. Grid voltage should be a negative number. With a weak or no signal, grid voltage should be about -3V. With a strong signal, grid voltage will be more negative due to the action of AVC (Automatic Volume Control). If you have spares, swap in a new 6A8 and 6K7.

Please post your results.

Good luck!