05-31-2017, 03:12 PM
Hi tubeforme.. I recently restored a model 66 myself. Based on my calculations for the voltage drop across both resistors which I believe is about 175V... both the 33K and 37K resistors may need to dissipate about one watt of power during normal operation. Using a 1 watt resistor is right at it's maximum rated power and does not allow for a safety factor. You minimally want a resistor to be twice the size it is expected to dissipate or in this case 2 watt. So for an ample safety factor I ordered a 3 watt resistor for my radio.
I recommend you check your screen voltage on the 6A7. According to the schematic chart it should read about 85v if the radio is operating correctly. In fact you should always check all voltages even if the radio seems to be working okay. Mine were all very close to the chart.
I recommend you check your screen voltage on the 6A7. According to the schematic chart it should read about 85v if the radio is operating correctly. In fact you should always check all voltages even if the radio seems to be working okay. Mine were all very close to the chart.
