Tested head unit on different ducer. Also did not post this earlier but the small ground wire inside the terrova shaft which ties to the 3amp fuse in the head had naked spots and corrosion. When I put my other transducer on this wire literally crumbled down in the shaft as I was threading it into the head. Luckily I was able to pull enough out to splice it. I guess that wire was the major source of the interference problems and was alleviated when I ran my own ground earlier. Just a heads up to not only check the head for connections, look in the shaft too if possible