Eagle Strata plus screen issue

[scruffy_fish]

My fish finder screen shows nothing, only a blank screen. I know the unit is working because I can hear it beep when I get into a different water depth. None of the buttons make any difference to the display. It's completely sealed so I can't get into it to find out what's going on.

Is this unit toast?

If it is, will I have to change out my tranducer if I buy another model Eagle fish finder? I'd like to upgrade to a color unit, but don't want the work of completely rewiring for a new unit.