He called in.
Five zones.
One solenoid always gets power (zone 5) even if the controller is turned off.
Zone won't shut down without killing feed on main line.
One solenoid finally burnt out from constant voltage. He replaced.
Told him to start at controller.
First unplug. This makes sure no power coming from other source, like lighting wire or new electrical, shorting across control wire.
When this verifies no other power source plug back in and disconnect all zone wires, test voltage at each terminal. Also check zone 5 when zone 1 or 2 is on. If any power coming out of zone 5 terminal when zone 1 is supposed to be active then bad controller.