Dolphin Stops

I OWN THIS SAME ROBOT SINCE NOV 2011 AND NEVER HAD A PROBLEM.
NOW IT STOPS AFTER BETWEEN 10 AND 20 SECONDS OF RUNNING.
HAVE CHECKED POWER SUPPLY , CLEANED IT , ETC .-
I TURN IT ON AGAIN AND THE SAME HAPPENS...IT STOPS

ADMIN REPLY: Call Aqua Quality Pools and Spas. They are just now organizing to sell and service Maytronics machines (516) 876-8643