Fish Finder Screen Problem

At times the unit will get a black edge around the outside edge of the screen . It doesn't always do it but most of the time. The black is about 1/2 an inch around the edges. Anyone ever had this problem? it just started doing it and no settings have been changed.

Call Donny at Boris Marine in Ft. Worth. He'll tell on the phone what that is or what is probably causing it.

You might want to tell us what unit you have and how you're using it when it screws up. . .