Actually I do have a Hardinge dovetail conversion Servo 8000 lathe made in the 80's. She's a killer, works nice. I got a bunch of spare Pittman dc brushless motors with it. If these are anything like JQ's they are real simple, just 2 leads, a + & -. If there's damage, either a short to ground/casing or the resistance in the winding is low or high you should be able to measure it with a basic ohm meter and then compare to one of your other drive motors. If the motor overheated resulting in damage that could be pricey to replace as the Z is the big boy motor. I am not sure but repair of this type of motor may also be an option. Hope you can nail this down soon.
By monitoring and trying to participate in this thread and off course "Hood", I feel I learned allot and that more servo machines are in my future seeing how simple this is set up with the geckos.
Robert