[RGK20m3]

Success!!!  I had the radio on, tuned to a station, monitoring the voltage across the AFC switch, and had the same readings as yesterday (.008v). I got to thinking about what could cause both sides of the 6H6 to not conduct, and thought I would check the heater voltage- had 6.61v at the terminals of the socket. Then I measured the voltage at the tube pin tips and heard a change in sound- I then had .5v across the AFC cathodes. As I tuned off the station the voltage would rise to over 3v in one direction only. I the turned off the AFC, retuned the station, turned the AFC on again and was able to find the 0v null between the voltage peaks and the AFC WORKS!

If you recall, when I tested the 6H6 I initially didn’t have a heater glow on the tester, and after I measured the resistance it tested good. I think there may be a break between the heater lead and the pin of the tube base.

Thank you for your observations and advice.