Question
sprinkler does not come on ......display is ok  it programs ok tried manual initiation did not work , individual stations  did not work either , installed  new battery did not work, 27 volts ac ok , i reset system by disconnecting battery and ac 27 volts  tried it again did not work WHAT COULD BE WRONG WITH IT?????

Answer
Did you test the voltage output on the stations?

Is there a weather sensor?

Is there a pump or master valve or both?

Was there any work done in the yard lately or in the basement if the wire runs through the basement?

Do you live in a harsh environment?

Have you traced the wires?

Is there a open circuit?

Do you think the timer was exposed to a power surge?

Is the water on?

What do you mean by 26 volts, where was that reading from?

Have you tried to wire a valve right into the timer to see if it turns on?