[RGK20m3]

Well, here is a new wrinkle-
Still haven’t hooked up the signal generator. But I decided to try a stronger broadcast signal and hooked up my milliwatt transmitter to see if a really strong signal might confirm AVC operation. Hooked the DMM to the AVC buss and voltage went to -9 volts on carrier, and dropped to -2.7v off carrier; when program material transmitted, reception was clear and of adequate volume. Decided to probe the B+ and audio volume did not change, but AVC voltage went to -13v
This to me indicates that the AVC is working, the audio stage is operating normally, and that the volume/gain drop is in front of the detector (as the AVC is compensating for the gain change).
New wrinkle is that the radio has been playing fine for a hour, and AVC is a steady -12.8-13v. Remember before I probed the B+ it was -9……