DMM breakout board -> spindle issues

I’m having a problem with the way my spindle turns on and off in Mach 3. Basically it turns on when Mach boots up and I have to manually stop it at the VFD or hit the Mach reset button (effectively calling an estop)
Mach won’t respond to an M3 code or using the keyboard F5 shortcut.

Yes, I could run jobs by manually turning the spindle on and off but I should be able to let my jobs gcode turn it off and on.

Here are a few facts to help.
1. Nothing I change in ports and pins other than turning the spindle completely off changes the behavior.
2. I reversed the two wires to the 17 block and it made no change. Various other combinations just didn’t turn on the router at all.

So, how are you guys setting up your Mach to operate the dmm board?

FWIW this is a K2 machine I’ve been running for ten years and have just rebuilt with all new motors/drives (dyn4) etc. I’m very happy with everything but am struggling with the spindle. I’m losing sooo much work time!