03-11-2013, 10:58 PM
Well I messed around a bit trying to adapt the 600's volume control circuit, but didn't have much luck. I basically connected the antenna and volume control like the 600's schematic shows. After doing this, the volume would peak about in the middle of the potentiometer and go down when I moved it in either direction. I tried different size resistors for the 200 ohm one, with not much difference. I did not disconnect the suppressor grid (pin 4 on the 77 tube) or the feedback capacitor (3 turn wrap) from the cathode. I'm not that familiar with the intricacies of the Detector/Oscillator circuit, so was hesitant to do so. Any thoughts are appreciated?