Can you check your connections and insure they are sound? I have a switch that let's me direct my ducer signals to either the console or to the back of the boat. Sometimes I don't push it all the way over and get similar as you....no image on right, bad image on left.

Otherwise, CS is right. Do you know anyone close by with another head unit? I'd put yours on their ducer and theirs on your ducer, see which way the problem follows then go from there.

Does the ducer look damaged?