[462ron]

According to the service info it says voltages are measured with a Philco 026 circuit tester. I’m not familiar with that tester so not sure if it’s a VTVM or a VOM. My understanding is a VTVM usually presents a certain fixed resistance or load to a circuit, usually 10 megs regardless of what range it’s set on whereas a VOM is rated at a certain ohms/volt like maybe 10K/volt so the load it presents to a circuit under test changes depending on what range it’s set to. A VTVM or DVM probably are 10M regardless of what range it’s set to.

 As for the finicky volume change, check audio shorting switch #29 on the schematic. It is used to short audio to ground while rotating the cone centric dial to eliminate noises and audio until you release the knob once you are on a station. Just a thought!

Ron