[R-390] 17 MHz osc pull from AGC

[Conard Murray]

Hey gang,
I'm working on a '62 Amelco and I have just noticed the 17 Mhz xtal
oscillator in the first mixer is pulling just under a hundred cps or so
in step with the AGC voltage. The stronger the signal, the further it
shifts. CW on the bottom 8 bands is chirpy when using the AGC. MVC is
fine. Signals above 9 MHz are fine.
Replacing the oscillator tube and mixer tube didn't make things better
or worse. The 150 volt line is dropping about a volt between AVC and MVC
mode with a strong signal applied. I don't think that is enough to cause
this problem .... is it?
I have had other lesser receivers with combined mixer/oscillator stages
chirp, but I refuse to believe the '390A is supposed to act in this
manner as some of the posts in the archives suggest. I have owned three
other 390As in the past 25 years and I don't remember any of them doing
this.
Has anyone else been able to cure this problem?
Thanks and 73,
Conard, WS4S