In the pursuit of old is new, I digitalized the operation of the 1960s 7186 turntable.  Key to its operation is power to the field magnet motor that drives the bridge, which needs traditional AC.  So, the k84 digital controller (or equivalent; here a Viessmann 5213) must be fed with analogAC (from white transformer) instead of digitalAC from control station.  The yellow cables are regular AC power, using two slots.  One slot controls the rotation direction (#4; 2 gray wires + yellow) and 2nd slot creates the pulse that starts the rotation (#3; gray wire + yellow). 
The decoder probably has a diode somewhere that controls power in, as digital power to the decoder from the CS (red+brown wires) is not affecting the operation of the turntable. (ignore the #1 red wires that control something different)
It is important to use a k84-type switch controller (instead of k83 solenoid controller), so that direction can be set by toggle switch (left-right) and so that the start is a pulse (not permanently on).
I control my layout with CS3+ and PC-based RocRail.  The latter uses directional arrows and a button for the start pulse (light blue block); the same can be achieved with just CS3 software.
video on YouTube

(sorry voor het engels)