[Al Skierkiewicz]

If you have a frame short with the motor installed and it is gone when you take the motor out of the robot, it just might be you had screws that were too long and were touching wiring inside the motor. It is unusual to measure +12 volts on the frame when nothing is running. If you indeed had a positive 12 volts while the meter's other lead was on the +12 terminal of the PD, you were measuring the 24 volt supply that feeds the PD less the 12 volts of the battery. Check the insulation on the cRio.