|
You're testing B+ at the right points. You said the buzz comes up "almost" right away: after the 80 tube lights up, right? Pull the 80: no buzz? Try another 80 if you have it. Put the 80 back and pull the 47 tube. Still buzz or not? Put the 47 back in and ground G1 of that tube to chassis. Any effect?
The volume control wouldn't affect an audio section buzz because it's way up front in the antenna circuit. The audio amp runs wide open in these sets.
Try a good ground to the ground wire provided on the set. Any difference?
Check R9, R10, R11: I think you replaced those? So they must be close to spec.
Is there any evidence that anyone was in there before you and changed the speaker wiring or does it look ancient and undisturbed?
Some of these sets were just buzzy. About the time this set was built they started putting hum bucking coils in series with voice coils to introduce a little voltage out of phase with the field, to cancel out hum.
__________________
Reece
Perfection is hard to reach with a screwdriver.
|