I got a 597 on the front of my boat that is losing its gps signal and then will not shut down with power button? I called Humminbird and its over its year warranty and they want $160 to fix it? I know its a long shot but anybody got any ideas whats causing this? One thing I thought of is my Hitek Holders are directly above my unit and then you add rods...reckon that could be reason for losing signal? But still seems like it should shut down with power button? I am not good with electronics but thought I would ask on here before paying the $160