I think I'm starting to understand a bit more about what GE did with this thing and why RCA has a Shark Fin wave and GE has more of a sinewave in the horz AFC , RCA has the lower diode of the phase detector grounded, and GE added filtering, WHY GE chose to change RCA's design, who knows
but that is neither here nor there when it comes to the problem with your set,
having never had too look that deeply into that part of my 16, i never really got that into it.