I have a Lowrance X51 depth finder that just went out on me after 4years. Before buying a new one, I was wondering if there could be an electrical problem. I'm able to turn the device on, but the screen does not display. Even the back light will come on for a little bit then turn off. The sound seems to work when I press the buttons, but the screen still does not turn on. I've checked the fuse and it's still good. I've never had any problems with it and have never dropped it. I'm just curious if there is something that I overlooked, any suggestions?