05-30-2022, 10:03 PM
The tuning cap cleaning I had done in the previous post turned out to not be enough. After reinstallation in the set but before reattaching any leads I retested the resistance between the rotar and stator....yes, I was still having a problem. This time it was more like several hundred Kohms but was not consistent and obviously not satisfactory so I gave the tuning cap a complete hot water soapy scrub and then rinsed with water and isopropanol. After it all dried and relubricated, the rotar/stator showed open throughout the tuning cycle ... amen. Reinstallation in the set followed by an alignment and its now working properly! Voltage on pin 4 of the 6SA7 oscillator tube is now 75 volts, much closer to the 80 volts specified on the schematic. I'll make a final post after the cabinet if finished. Thanks for all the help on this one!