Only my 797 is effected, does have anything to do with big motor or trolling motor running or not. I have a power AC adapter, while fooling around with it in the house, I dissassembled the unit, by visible inspection everything looks ok, but it is still blin king on/off, until you press on a "cooper" at the bootom of screen, then about 75% of the time the unit powers up and works fine.
Any know a good repair shop