furuno navnet intermittently not transmitting



Hi guys, I have a navnet 1 system with the 12 kw open array. I have a couple of questions:
first, I'm having a problem with the radar not transmitting occasionally. I will hit the transmit button with no response, then getting the audible alarm. I can hear the relay click in the display. there have been a couple of times when i have placed it on standby and it would not restart. Ideas??

also, I dont know the age of the c-map card but with a new card will the graphics be better?

Thanks, Chris
Fl Keys Diver/Chris
The 12KW NN1 unit would be the 1953 radar system. It was sold in a 10.4" display or BB format. Regardless of type, this radar has a power supply (PSU005) that sits between the display/processor and the radar scanner. I would recommend that you locate it and check the condition of all the connections. I would also check the connection at the back of the display and the connections inside the scanner unit. You could have some corrosion/intermittent connections going on. When you take the unit to transmit, you should here a relay in the display (like you have been hearing) and the PSU005 "Click". When you do get the alarm, press the ALARM button on your unit to get more details about the alarm.

Newer C-Map charts for the NavNet 1 might offer a bit more details than the chart you have. Jeppesen updates these charts twice a year. It wouldn't be a big change other than updated information. In general the C-Map NT+ charts will have the same coverage area as your old chart but updated with the newest information.

(Why do they keep telling me "Nice Hollween Outfit". I like my ears)
Hey Johnny, so do I understand correctly that grounds are crucial on this for the radar to start?
It depends on the ground you are asking about. The gearbox grounding lug on the outside of the gearbox is more for Safety/protection, as is the chassis ground wing nut at the back of the display. The unit will "turn-on" and function fine without them connected. If you do have a ground connected, that is not a good ground, then it can cause you problems such as grounding loops.
Just a follow up to this not transmitting thing, I took the boat out a few days ago and discovered that if the radar parks at 90 degrees or so to the centerline of the unit, it wont start, and it alarsm no bearing pulse.if the antenna is manually turned to just beyond paralell to the centerline, it starts everytime. Any Ideas?? Thanks, Chris
fl keys diver,
Your problem would be either a bad motor or the motor start circuit on the interconnection board. If the motor always (100% of the time) starts when in certain positions, then it sounds like you should look into replacing the motor. The motor start wouldn’t be affected by the position of the array.