[tbone]

This has been an interesting post to say the least. Intemittents are the worst.

If I read this correctly, the DC voltages seem to be stable when working or not. The AVC voltage will vary based on signal strength, so i think it will be fairly high negative with your transmitter.

Have you tried the radio on a shortwave band to see if the problem follows? I know SW stations are a not the most stable, but some of the time standard stations are. WWV on 5, 10, and 15 are reliable. CHU pumps out a strong signal on 3.330 nights, and 7.850 days. I say this because a different set or section of coils is used which may give a clue.

The other thing I have seen is trimmer caps intermittently shorting out. The mica can get cracked, or it can be dirty. May be worth cleaning them and checking for issues.

I really feel the problem is before the 6A8 because you have stated putting your finger on the grid cap brings in the stations, but immediately goes away when removed. You should get 20-30 ohms between A and G on AM, and less on shortwave.

That’s all I have.