I have a new boat. It has the Ultrex Mega DI transducer built in. It is linked by Humminbird network to a Helix 12 G3N Mega + DI. First trip out I deploy the trolling motor and unit works fine. 10 minutes later, I look down and see the screen image on DI is locked up. I could not think of anything except to power down and restart. Unit comes up fine but now shows no images on sonar or DI. Anything simple I am overlooking before I take it back to dealer.