Furuno Analogue Radar Help


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I'm based in the UK and have been given a Furuno radar system without a radar cable but have managed to acquire another radar with the correct looking cable in the hope to get it to work.

The system is an RPU-015 NavNet VX2 with an open array radar RSB-0070 RTR059. The radome with the cable is an RSB-0071 RTR057. The cable has the correct DJ-1 connector for the RPU-015 and the connectors fit the RSB-0070 but don't want to power anything up without checking first. Some photos for reference:


Any help appreciated.
The wiring on the cable in the picture appears to be compatible with an RPU015 (NAVnet vx2 Black Box) dome radar connection as you have stated. That cable --although it will physically connect to the 059 open array-- is missing critical wires in the 13-pin connector as well as an additional 2-pin connector. In short...that cable is not compatible with your open array radar.
Thanks for the reply.

I've been doing some more research and from what I can tell it appears that's not the case, however I'm not an expert.

From what I can gather the open array XN12A-RSB-0070-059 is model 1944C-BB - a 6kw 24rpm 64nm 4' open array radar. The radome is 1834C-BB which is a 4kw 24" 24rpm radome. Both models in the installation manual utilise the same cable with a ground connection and three connectors - 9-pin J801, 4-pin J802 & 13-pin J611. The internal boards are basically the same being RU-9390 & RU-9390D. Neither radar require a 2-pin connection for the RPU-015.
I've attached both interconnection diagrams for the dome (057) and open array (059) radars. If you look at the antenna unit connection (J611) on the "dome" attachment and compare it to the same on the second "open array" attachment...I think you'll note the differences I was referring to (specifically, pins 2, 4 & 6). Additionally, the J822 2-pin connection is listed in the second attachment for the open array. Although they are noted as being spares, there still should be a 2-pin J822 connection that they plug into. You may also note that the "dome" attachment shows "MJ-B24LPF0002" as the cable number with (17C...) that refers to the number of conductors being 17. On the "open arrray" attachment, "MJ-B24LPF0005" cable with (21C...) that refers to the number of conductors being 21. I hope this helps clear up any confusion.


  • 18X4CBB-Dome-057-RadarInterconnectionDiagram.pdf
    120.4 KB · Views: 1
  • 19X4CBB-OpenArray-059-RadarInterconnectionDiagram.pdf
    119.4 KB · Views: 1
Thanks - very useful.

As you say it appears the connections are the same apart from the open array having repeated motor signal connections in JB24:

Motor- to pin 2
Motor+ to pin 4
Motor+ to pin 6

It seems odd to manufacture different versions of a cable but then Furuno seem to do everything their own way!
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On the RPU-015 DJ1 socket:

Pin 1: Motor+
Pin 4: Motor+
Pin 19: Motor+

Pin 5: Motor-
Pin 22: Motor-

Pins 1, 4, 19 all share continuity and Pins 5 & 22 share continuity. This basically means the additional radar connections are duplicates. Presumably this is for current carrying purposes as opposed to signal unless there's a carrier? There are two main 12v supplies on 10 & 11 (+ve) and 14, 15 (-ve).
While I appreciate the attempt to make a cable for a dome radar interface/run an open array radar, the engineers designed two separate cables for a reason. I can only tell you that the cable you have for the dome will not run your open array without those extra wires. As a technician, I cannot bless an install that isn't by the book.
I'm not asking for a blessing - and we all know engineers design systems to work across multiple different pieces of equipment and so have redundancy. If it won't work that's fine (it only took 3 months to source this cable!) but I'd be interested as to what the additional motor connections are for exactly?
FWIW I'm not planning or advocating installing an open array with this cable - I have no idea if the open array works so want to test it before investing any more time and money. The RPU-015 works with the 1834 radome and cable at least.
In the UK a new MJ-B24LPF0005 cable is £400 and a 3 month wait time. The open array radar isn't worth much more than that so if it's toast then it can just go in the bin.
The extra wires in the 13p were added to provide extra current to the motor in order to run the larger array. They did this instead of putting larger gauge wires on the original motor +/- signals of the 4p connector. So basically, without the extra wires, the open array's motor won't have enough current to operate properly. For testing purposes, connecting that cable will be fine for a short test. If it works, then getting the appropriate cable --as you have said-- would be the way to go.
Thanks - that's what I thought. Raymarine do a similar thing but just double-up on the main power cables rather than separate CPU / Motor as Furuno do. It's not so much current draw but voltage drop over long cable lengths at 12v.