Question
Intermittent behavior may be caused by a loose wire on the motor connector or encoder connector or may be a result of a poor connection between circuit boards on the ECU.
Remove the 3 screws holding the faceplate to the motor housing pull the faceplate away from the motor housing. Inspect the wires on the motor and encoder connectors to look for loose connections. Repair any loose wire connections.
Inspect the interconnections of the circuit boards to ensure both vertical circuit boards are seated properly into the baseboard.
Note: on older pRESP/platforms, the circuit board spacers were plastic and did NOT rigidly fix the vertical boards in place. After extensive use or transport the Motor board may become dislodged leading to intermittent operation of the phantom. Re-seating the Motor board onto the baseboard should correct the problem. Securing the motor board to the microprocessor board with threaded spacers and screws will solve this issue permanently.