[tbone]

Well I am pretty close to finishing the electronic restoration on both the amp/power supply and radio main chassis. I am going to ohm out my coils again since I was in all of them at one point, and also ohm out each B+ buss to make sure I have no shorts or surprises. I like to do this before power up.

I have a question about the audio shorting switch (74) on the tuning shaft. What is it's purpose, and how is it supposed to work physically? I have put it back the way it was found, but it appears to be shorted to ground intermittently where it rubs on the auto tuning collar. The contact that passes through the flat part of the shaft is not shorted, so that's good. My thoughts are that this switch is supposed to mute the audio while using the automatic tuning. Originally my radio had intermittent audio when manually tuned, which falls in line with what I am seeing now (intermittent short).

The schematic lists service bulletin 273 with reference to parts 6 and 16. The literature I received from Chuck did not have bulletin 273.

I appreciate your help in determining what I need to do in order to get this switch working properly. Attached is the schematic and picture of the questioned contact.

Thanks for your time.

https://www.flickr.com/photos/152428891@...ed-public/

http://www.nostalgiaair.org/pagesbymodel...013255.pdf