Ford Audio System LCD disply unit?

My Ford Mondeo Radio / Audio system works fine but the text in the LCD display window is not visible, the back light is there and all the tape, cd and radio controls are fine. Can this be fixed? A major problem would be if I lost power to the unit I would not be able to enter the code in to reset it to operational.
Can anyone help with this?
Regards from Ian in Eccles.