More Teletype Questions

My teletype is the TWX type with a 101C data set (modem) in the stand. The CCU has a touch tone dialer and 6 lighted pushbuttons at the bottom. It appears the CCU wiring is mostly an extension of the data set wiring. There are two 50 pin connecters routing wires between the two. I am trying to track down the local mode current generator. I believe it originates in the data set. Anyone know if this is correct? I can't find any circuitry in my CCU which generates this. With the data set connected I get no local mode current so the selector continously cycles. I can disconnect the data set and inject a current to get it to stop. Does anyone have a schematic for the 101C or the CCU in the teletype? There are some descriptions (text only) in the ASR manuals but not enough for troubleshooting. My only other option is to start trying to trace the wiring. Given the 7 circuit cards and numerous relays in the data set, this would be a very big job. Thanks, Bill