[Eliot Ness]

Welcome to the Phorum Steve 

I'll briefly touch on one of your radios, the 1936 Zenith 6S52.  A six tube radio it was the first in Zenith's lines of "Big Black Dial" radios that are very popular with collectors.  Although it's not apparent now, with the dial lights on the dial is actually fairly colorful due to bands of color on the rear of the dial face.  It also has a fairly deep chassis that should be easy to work on with lots of room.  Unfortunately, the correct original wood knobs might cost more than the $50 you paid for the radio, but that's just a fact of life with the Z knobs.  This site has a close-up of the correct knobs:

https://www.radiomuseum.org/r/zenith_6s5...h5619.html

It looks like you'll need two round, one pinched, and one pointer knob.  There are very nice reproductions available from:

http://renovatedradios.com/productlist.p...ondary=120

For reference it looks like you'd need a K16, K18, K15 and K14 for tuning.  I suggest just putting a set of cheap generic knobs on it until you are successful restoring it, and then do more research for the exact knobs used... those are just my best guesses since the only '36 I have is a 12 tube that uses a dual tuning knob.

Also, please don't power up these radios until you at least replace the electrolytic capacitors and out of tolerance resistors.  Below are two very clear schematics:

https://www.tubesandmore.com/sites/defau..._pg7-1.png

https://www.tubesandmore.com/sites/defau..._pg7-2.png

There is a long metal resistor mounted to the chassis shown near the top of the schematic.  These multi-section units are called a candohm and you should replace all sections if any of them are out of tolerance since they have a tendency to short to the chassis (I personally replace them all just to be safe).  The 11M is actually 11K ohms, Zenith used a M to indicate K ohms back then.  Good Luck and have fun!