You did really well! I had a problem with an intermittent 25mm motor. It ended up being that where the motor mounts to the gearbox the screws had vibrated loose. It meant the motor came out of alignment here and there and the pinion would bind the gearbox up. I took it apart and tightened everything and it was fine. Now after each event its part of my routine to strip the motors down n tighten everything up.