Trackfish 6600 stops and starts again by himself many times in a few minutes; first screen map thouthand miles away from real boat position !

Try a factory reset - that worked for me when my Northstar Explorer 660 stopped by itself again and again. You find this reset commando by pressing MENU twice and then under Systems menu, if I remember it correctly. There is also a RAM Clear commando. This is done by holding the MENU button pressed when the GPS is switched off. Keep it pressed while switchin on the GPS, still holding the button pressed until the RAM Clear menu appears. You will probably loose all waypoints etc. by doing this so try Factory Reset as your first alternative. Good Luck! // Jonas, Sweden