Always turn off your electronics (radar displays, chartplotters, multifunction displays, etc.) using the unit’s Power Button. You should never power electronics down by shutting it off with a breaker or switch. :noway
Verify each piece of equipment is protected by its own properly sized fuse or breaker. It’s a good idea to treat recurrent blown fuses or tripped breakers as a symptom rather than the problem (low batteries or bad connections can often cause a fuse to blow, or a breaker to trip). :thumbdown
Never try to “fix” the situation by replacing blown fuses with those of higher amperage than called for by Furuno's manufactured recommendations – doing so can cause serious damage your electronics or even result in a possible fire hazard (due to wire overheating) if enough current is present. :shock