this unit quit while driving and the operator said he heard a loud humming noise like a pump motor. I checked and found a contactor welded together and it opened at my touch and the code -51 disappeared. I'll replace the contactor tip kit and see how it goes. Thanks for the suggestion.
troy

check the current limiting resiter that bridges over the line contactor. it allows a small current into your controller to pre-charge the capacitors so they can self check before startup.

this might help E50XM2-33 #f108V232294