10-03-2014, 09:23 PM
According to this schematic, it does look like a 250K with a loudness tap. Tap isn't super critical.
As far as your volume issue, check to make sure your pot has continuity (250K across the outer terminals), and check R13, 850 ohms, to make sure it's good. I suspect it's gone a ways up in value, and since it looks like a bias resistor for the tube as well as the ground return for the volume control it could be giving you problems.
Also check R10 and R11 (both 1M ohm) as these are in your AVC circuit and almost assuredly have gone up in value. I've seen these go as much as 500% high, or open.
As far as your volume issue, check to make sure your pot has continuity (250K across the outer terminals), and check R13, 850 ohms, to make sure it's good. I suspect it's gone a ways up in value, and since it looks like a bias resistor for the tube as well as the ground return for the volume control it could be giving you problems.
Also check R10 and R11 (both 1M ohm) as these are in your AVC circuit and almost assuredly have gone up in value. I've seen these go as much as 500% high, or open.
