Yeah, I had a Lowrance early 3D unit do pretty much the same thing. I forget the exact model number of that Humminbird, but it was an early fairly large screen side scan model. Where we used those was a lot up in Canada on a temporary mount in a S14 or S16' flat bottom Lund and they took quite a pounding when we went out in bigger waves. It turns out that what illuminates the screen isn't just a light bulb, but a circuit board that becomes obsolete and no longer available. I still have that Humminbird on the work bench up north and the bottom image is still there, but the only way I can see it is with a strong flashlight. The little lakes that I fish up there are just bowl shaped with weedy edges, so I haven't needed a depth finder there. I've found that the best way to fish walleye structure in Canada is to go with other guys who own depth finders that want to drive the boat.
