I have a almost new(been used about 6-7 times) hummingbird 575 unit. It has worked every time i have used it until last week. When i turn it on it says transducer not connected? I have plugged and unplugged the cable 5-6 times and it still says transducer not connected? Has anyone had this problem and / or know how to fix it? Any help would be great ! Thanks ! Bigfish5