I just got done laying the wire for my bow mounted X-75 on my Tracker Pro Team 18. I also have an X-85 mounted on the console. I tried grounding the X-75 to one of the mounting bolts for the trolling motor but it kept cutting out. The mounting bolts go thru wood. I then grounded it to an aluminum stringer next to the trolling motor. The power lead goes directly to the cranking battery using part of the existing factory wiring. My X-85 is also wired directly to the cranking battery. I had both operating in simulation mode for about 15 minutes b4 the X-75 cut out again. I pressed the power button several times but no luck. I noticed that the screen flashes but does not come on. The X-85 operates normally. What am I doing wrong??