[Nick3092]

Not sure if anyone is still paying attention, as I seemed to have burned through all the easy/quick fixes/checks. But I went back tonight, and was going through the alignment again (even though I knew it was futile going into it). Not sure if this will spur any new ideas, but I noticed something new tonight.

I was trying to do the RF alignment again, starting with the SW oscillator. I had the dial at 18MHz, had the sig gen at 18MHz, and hooked up to the red antenna terminal. I had 4B tightened all the way down to start the alignment. As I started backing it out, the AVC spiked, and the speaker started motor boating. At the peak of the AVC spike, the motor boating went way. I checked with my DMM, I had -38v on the AVC line. I disconnected the sig gen, no change. I turned off the sig gen completely, no change. Turning the dial off 18MHz would reduce the AVC.

So, that's my new observation. The radio is going into oscillation and motor boating while adjusting the SW oscillator, even with no SW signal even near the radio. If I touch the grid cap of the 6A8, the AVC immediately drops. As soon as I take my finger off, it spikes back up again. Changing the dial removes the oscillation.