I bought a 75 year old house recently, which has what I'm told is a 40-50 year old irrigation system. All underground lines are copper, and it works great, except for one thing. The controller, which looks about the same age, has two dials. One for zone and one for minutes. No days. Nothing else. The only way to operate the system is to turn it on manually, and, since the "minutes" dial is inoperative, turn to the next zone when appropriate. Since I travel frequently, the system is rarely used, defeating the purpose of underground sprinkling, in my opinion. I would like to upgrade to a modern controller, but the existing controller and valves are 12 volt. I understand that newer models are 24 volt, which brings me to my questions. Can I use a 24 volt controller with this system, or will it fry the valves? If not, how do I step down the voltage to 12V? My contractor (who is terrific, by the way) has quoted me $1000 for the upgrade. This does NOT include changing out the valves to 24V units. With controllers going for just $50-$200, I am looking for another option. Any ideas?