Look at the second stringing diagram (page 6-8) in the Rider manual for RA-112:
http://www.earlytelevision.org/pdf/d...-rider-tv6.pdf
I believe that's what I looked at when I restored my RA-113. My tuner had a busted gear, so I had to pull the mechanism completely apart, and somehow I got it back together correctly.
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html