Problems with a Piedmont

[Carmine]

If anyone was wondering what ever became of Doug's giant Zenith console, the Emperor-like mega console; it landed on its feet (casters) in a loving home just outside of Toledo, OH. The set's real name is "Piedmont".



However, it has recently developed an annoying audio hum. The hum is not related to signal level or input from the converter box, it's present with/without a signal, even with snow. Interestingly, I can modulate the frequency of the hum by using the brightness and contrast controls, but not its volume.



The obvious conclusion is a shorted cap, I would think somewhere in the video or HV circuits. There is no degradation in picture quality.

Anyone have an idea where I might want to start poking around with a dull stick? Haven't bothered to remove the back because short of an exploded cap, I know this isn't going to be something visually obvious to solve without a schematic (or the help of someone who has one).

BTW, I love having this set as a daily-driver in the living room. Strangers really freak-out when they see this huge console as your "main" TV. Little do they know that as crappy as modern programming has become, investing in a fancy HD flatscreen makes about as much sense for us as buying a Lamborghini strictly to drive to church on Sunday.