[Reece]

I don't have the schematic for your radio, but here's my 2 cents: with a concentric control, the center knob controls the rear pot, the outer knob controls the front (closest to panel) pot. In most volume wiring, when the volume is turned down the wiper of the control approaches a terminal which is at ground or close to ground potential which helps to kill the volume (the volume is also reduced because the wiper is farther from the other terminal which supplies the audio signal.) Looking at the control from the rear with the center terminal of the three pointing at 12 o'clock, the "ground" terminal would be the one pointing at 11 o'clock. Check the schematic and see if the 11 o'clock control is connected properly with respect to ground. Hope this is not far off!