Damn - just read Bill's posting after days of trying to sort this out with Raymarine
(and other problems). Of course the guy at support expressed surprise with my problem and suggested I had voltage fluctuations (hard to imagine when my house bank is about 900 Ahrs).
I have the E120 in a Norseman 447. Build date for my unit is March 31, 2008 at 1300; now looking at having to replace radar
scanner and chartplotter
La Paz, Mexico