Hi Robert,
Use your Fluke to measure the voltage of one of the pins directly on the PP cable connector. Unplug it from the C11G, put one of the probes on one of the direction pins, say pin 3, and the other on any of 18-25 (ground). Now using the arrows of the corresponding axis, jog it alternately each direction. The direction pin should be changing its state and you should see the readings reflect it.
Dan