03-14-2021, 08:22 PM
And now, the end of the story.
Voltages all close enough when measured from the right place. Bought a sheet of mica, split it to .001-.002 thickness and replaced all three variable cap trimmer insulators. Now I can adjust them all to between 300 and 700 picofarads (if I read my LCR meter correctly). But the biggest problem was the 71A tubes.
There was only low volume. When I pulled one of the 71A's, the volume doubled. I tried 5 different 71A's, and finally got the proper volume. All the tubes tested fairly high. But I guess they really make a difference in this radio.
All said and done, it was fun. And thanks for the help to all. Now I'm starting on another 20. This should be alot easier. At least re-stuffing the bakelite blocks takes less than 5 mintues each, now. Got one or two more 20's to follow.
Pat
Voltages all close enough when measured from the right place. Bought a sheet of mica, split it to .001-.002 thickness and replaced all three variable cap trimmer insulators. Now I can adjust them all to between 300 and 700 picofarads (if I read my LCR meter correctly). But the biggest problem was the 71A tubes.
There was only low volume. When I pulled one of the 71A's, the volume doubled. I tried 5 different 71A's, and finally got the proper volume. All the tubes tested fairly high. But I guess they really make a difference in this radio.
All said and done, it was fun. And thanks for the help to all. Now I'm starting on another 20. This should be alot easier. At least re-stuffing the bakelite blocks takes less than 5 mintues each, now. Got one or two more 20's to follow.
Pat
