If you are able to use a voltmeter, test valve for voltage while you have the timer in the "on" postition where water usually enters unit.
If you have 120VAC at the valve, then you know that your timer is sending correct voltage to valve log.
Check all of your connections to see if they are seated properly and ground wires also. Make sure that your hoses are not kinked and valves turned on, and screens cleaned.
If there is no voltage to valve log, then you know that it is most likely the timer. If you can read and Esterline Chart, then refer to that... should be on the technical manual beneath the panel, and find which wire to check on timer, test for voltage at proper time.
Just some thoughts...