[Hallicrafters] SX-96/100 Oscillator pulling

[Ka9p at aol.com]

After reviving an old SX-96 (but not having recapped it yet) it sounds  great 
but exhibits a kind of pulling up on Band 4, which I'm sure I've seen  these 
radios do before but can't recall the fix.
 
When the BFO is engaged, it's as if the HF oscillator is pulled kind of in  
proportion to AGC voltage - that ring a bell with anyone, or anyone have some  
hints for what to look at first?  The radio's eventually due for a recap,  but 
I'm hoping to put this right for now and save the recap for retirement  
someday :)
 
Thanks, Scott