Digitech Studio 400

Hi guys.
Merry pre-christmas to y'all!

A friend of mine just came back from France with a Digitech Studio 400. It worked fine when he was in France, but when he unpacked it after a rough flight, the display shows nothing, only the backlight was on. I was thinking it could be the display contrast function, but then again, my friend is an experienced sound engineer, and I guess the unit was not powered up while on the plane.
Any thoughts what might have happened?

Thanks in advance.