Humminbird transducer not connected help!!!!!

I have a Matrix 10. When I power the unit on it says transducer not connected, then it goes into simulator mode.When I go into the diognostics screen the self test says "passed".I purchaced a new transducer and it does the same thing. I have tried all the troubleshooting the manual has and nothing will fix it. I went to Humminbird website and it will cost $64.95+ shipping to get it fixed. I only paid $150.00 2 years ago. Anyone have any suggestions on what to try next. Thanks Ronnie