I have a raymarine radar with rl70c display on my 2002 FV 342. It used to work fine, then began to be finicky and would at times say not responding. Now it only works with the engines turned off. As soon as i fire the Port engine it makes the radar screen say "Scanner not Responding". Starboard engine has no affect. Even when running at higher RPMS putting out a decent alternator charge it still says not responding. Im not sure where to start. I plan to being by checking all connections but hoped someone would maybe have a hidden trick up their sleeve to fix it.