I believe the RA-112 and RA-113 are pretty similar. They are covered in the same Sams manual. This RA-113 article has some restoration notes that may be helpful:
http://antiqueradio.org/DuMontRA-113Television.htm
I was playing my RA-113 last night while wrapping Christmas gifts in the TV room.
Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html