When I first turned on my RD-1200 sprinkler system this summer none of the zones would work. I eventually determined that I have intermittent voltage to the MV terminal in the controller. In manual mode the main valve will actuate for a couple seconds and a zone will turn on for that couple of seconds but then shut back off. If I connect 24VAC directly to the MV terminal, the zones will turn on and run normally. Is it possible to repair this controller problem or should I purchase a new one? I