11-29-2017, 08:24 PM
Got into the volume control. That's an impressive little piece of electro-mechanical apparatus! The schematic says it should be 500K. I measure 3.3 meg. The variation in resistance from one side to wiper seems to be a nice, gradual change from 0 ohms to 3.3 meg. The part number is 4093.
If it should be 500K, is there a way to refurbish the carbon resistor? Or, will the control still work but volume adjustment would occur in just partial rotation? It appears that the volume control is providing the bias for the grid on the driver tube from one end and signal from the bypass capacitor on the other. Perhaps sufficient bias is maintained even with much higher resistance in the circuit??? I suppose time will tell!
If it should be 500K, is there a way to refurbish the carbon resistor? Or, will the control still work but volume adjustment would occur in just partial rotation? It appears that the volume control is providing the bias for the grid on the driver tube from one end and signal from the bypass capacitor on the other. Perhaps sufficient bias is maintained even with much higher resistance in the circuit??? I suppose time will tell!
