[RGK20m3]

That is the direction that I was going to try; injecting an audio signal to see if that stage is normal. I also am going to try determining current draw through the circuits in the audio stage, as that obviously affects the bias voltages.
AVC voltage is -2.8v, and only varies by a few tenths. Decoupling cap and the bias resistors (27,33) have been replaced. Screen voltages on the mixer and IF tubes is rock steady; decoupling cap has been replaced. I did measure if there was any voltage present on the ground points to the chassis, none. I did disassemble the volume potentiometer and cleaned it. I did clean the tube sockets and tension the terminals. Also poked every wire, coil,and solder joint with no voltage fluctuation or popping from the speaker. Hopefully the 6A8 will fix it, but hope is a bad strategy…..