Buster -
If you have already replaced the controller, I would suggest that the problem is most likely in your valves. Are zones just randomly turning on, or do they go in a methodical order? If your controller is in the off position and your valves still turn on, the particular zone or zones that are turning on may have either sticking valves or a bad solenoid. There is also a possibility that your system may have a short in the wiring, which is causing this to happen. What is your static water pressure, and how old is the system?
Tony Posey
Ridge Run Landscapes