09-02-2026, 10:01 PM
MrFixr,
I did not try to fire it up with the 12AV6 installed. The underside of the chassis was really a mess. I've tried subbing a couple of NOS 14B6's, 7A8's, and a 50L6 (all tested good) to see if maybe the tubes had failed, but no change. I did find a 22K resistor that was not on the schematic attached on the 7A8. That resulted in the voltage measurement on pin 5 of the 7A8 and pin 6 of the 12BE6 dropping from 56v to 46v which is closer to the 40v from the schematic. Clipping the 150K resistor made no difference. C302 had been .005, but I will try a .05 tomorrow, and recheck that R202. The volume neither increases or decreases and no change in the motorboating. I'd say that the put-put is about 120 cycles per minute, steady and rythmic. More tomorrow. Thanks friend, Joe
I did not try to fire it up with the 12AV6 installed. The underside of the chassis was really a mess. I've tried subbing a couple of NOS 14B6's, 7A8's, and a 50L6 (all tested good) to see if maybe the tubes had failed, but no change. I did find a 22K resistor that was not on the schematic attached on the 7A8. That resulted in the voltage measurement on pin 5 of the 7A8 and pin 6 of the 12BE6 dropping from 56v to 46v which is closer to the 40v from the schematic. Clipping the 150K resistor made no difference. C302 had been .005, but I will try a .05 tomorrow, and recheck that R202. The volume neither increases or decreases and no change in the motorboating. I'd say that the put-put is about 120 cycles per minute, steady and rythmic. More tomorrow. Thanks friend, Joe
Courage will follow when Faith takes the lead.
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
