It has the 12 v input, a light is on on the bob at the end of the input pins. It makes a subtle high pitch noise when I connect any of the input pins to the ground pin, but it does not register it in mach 3.
All grounds are together, but now I.m testing it with a single wire.
Pc gnd is not connected to anything.
The only difference with this bob is that it has a P14, to which all I ran all ENBL- from the drivers.