my dolphin 2002 dynamics plus problem.

by Eli Reytan
(Bergamo, Italy.)

When i start my dolphin it’s goes for 1 minute forward and then when he change direction only one side is rolling for some seconds and then it's stop.
Then I have to turn off and turn on again and again.
My dolphin is cleaning actually only for one minute and only forward.
Should I have to change the whole motor group?

Pls help.