[R-390] R-391 Motorboating with RF Gain beyond 7

[Mack McCormick]

My R-391 has developed motor boating (audio oscillation) when the RF gain
control is advanced beyond 7.

If you're run across this issue I'd appreciate knowing how you fixed it.

I have rebuilt about a dozen R-390a and have a full test equipment bench.
I'm just hoping for a head start before I begin troubleshooting the IF
stage. Yes, I tried the usual searches but didn't find anything.

Thanks in advance.

73,

Mack
W4AX
https://www.qrz.com/db/W4AX