Great score -- congratulations! This set has an interesting electronic design, with air variable capacitors in the tuner and an outboard horizontal/AFC chassis, and it performs well after restoration.
This article has some restoration notes on the 661-P:
http://antiqueradio.org/CapehartFarn...Television.htm
If you send me an email via
http://antiqueradio.org/contact.htm, I'll send you some close-up photos of the knobs on mine.
Regards,
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html