09-10-2020, 04:46 PM
For grins and giggles, I pulled my 71 off the shelf and looked at the oscillator signal on the scope taking the signal at the cathode. Beautiful sign wave at 1500 kc. Amplitude went down as I tuned lower. Plus the shape of the waveform degraded severely. The cathode resistor is original and measures 11k. I paralleled another resistor to bring the cathode resistor down to about 8.4 k. The cathode waveform on the low end of the dial increased substantially, though still distorted. At the high end of the dial, the waveform was good but with slightly less amplitude than without the resistor. I left it in the circuit cuz the radio seems work a bit better on the low end of the dial.