Chicago Burbs, IL
It sounds like it had movement, so I'm thinking more a connector issue. As eyeamred2u said, the red/black is power to the motor, but the optos control the stages and where the CPU thinks it is.
Step1) do a full test of the whole machine of the basic functions. Inventory what works and what does not. Every switch, solenoid and even the flashers. Test the switches with a ball, not your finger. A few non-sequitur switches not working could indicate a matrix issue.
Step2) If you get it moving again, try running TEST 14 to run the MPF through it's paces. There's a lot of really good intel displayed on the DMD.
faz
