If it is the LCD, which it sounds like, it would not be economical to repair.
I would suggest replacing the unit with our FCV628. You can read more about it here: http://www.furunousa.com/Products/Produ ... uct=FCV628
Yes, the transducer will plug in but you will have to change out the power cable.
Depending on transducer you might not be able to use the accu-fish or bottom discrimination.