09-09-2013, 07:34 PM
What you got is a volume control that does two things. The top half controls the level of RF that go to the input to the mixer. The bottom controls the cathode bias on the IF amp. So I would check #34 and the 35 tube. When you look at the schematic it does look confusing with the B+ going to ground thru the volume control.
GL
Terry
GL
Terry