Thanks guys. I will try to get the part numbers off the computer today. I've had it off once before.

On another note, I checked the wiring on the compass and everything looked OK. I found that if I rotate the compass the reading on the control unit changed. However, there is a flashing 'C' on the display when in manual mode. I'm assuming that means it needs calibration but don't know how to do that. Does anyone have a manual with the calibration procedures?
Joe