Fuse requirements for DF5 Pro

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Jim,

Q1: If one checks continuity between the + and - power lines of a DF5P MFD, would it normally show continuity (ring-out as "shorted") or has mine suddenly gone bad for some reason?
A1: With the power/transducer cable disconnected from the display, the no continuity should be measured when tested from the cable's power leads. Should you instead find continuity, then the cable would appear to have a short and should be replaced. As the Power/Transducer Cable are produced as s single component, it must be replaced or a Dragonfly Power/Transducer Extension Cable may be added to the cable to essentially bypass the Power/Transducer Cable's power leads. The Power Cable / Transducer should be sent to Raymarine’s Product Repair Center to be bench checked / serviced.

If in a pinch for time, you may want to determine whether the short is within the block on the cable's power leg. If so, then the block may be cut from the cable's power leg and then the cable's power leg may be spliced back together (simply splice leads of the same color).

Q2: What are the proper fuse requirement for my wiring situation? Review of the manual shows that a 5A inline fuse should be used between the distribution panel and + power line to the DF5P (see pages 23 & 38) but elsewhere the specifications are for 2A slow blow or 3A thermal fuses (pages 39, 132).
A2: The correct fusing for Dragonfly 4/5 displays is a 2A slow blow fuse. A 3A thermal breaker would be used for circuit protection systems featuring thermal breakers rather than fuses and the circuit supplying power to the Dragonfly 4/5 display was powering another device as well as the Dragonfly 4/5 display.