Do you have another transdcuer or someones boat you can try your unit on? Its important to know if it the unit or the transducer is causing the issue. If not, check the member map and see if anyone lives near you that you might could meet up with.
You may want to check the pin connections on the transducer connector. Slide it on and off and see if its lose or easily comes off. If so, try bending the pins very slightly outward to see if it helps any. The HB pin connectors are know for getting lose and losing connection.
Good Luck,
Robert