NavPilot 500 just lost RRU signal/sensor

[musicmanjer]

Aloha Furuno Wizards,

I have a NavPilot 500 system. We had a Tsunami threat so we took our boat offshore last week. The autopilot was working just fine. We came in safely, but the very next day I get a Rudder Sensor error on my display. I checked connection to the system controller and then I checked connections at the FAP 6112 sensor. I re-spliced (soldered and heat shrink) connections again at sensor ( I replaced an old FAP-6110 and used the wire from it) and checked operation again in case there was water intrusion or corrosion. Nothing. It seems since it is an analog potentiometer, it would have some feedback and not just stop working altogether?

Is there a way to test the sensor via ohm meter? Could the controller have a bad connection at the connector? What are some tests I can do to diagnose?

I depend on AP for fishing almost every day. I ordered a tested used FAP 6112 and 511 processor from a boat electronics upgrade as it is a critical tool for us. Am I missing anything??

Mahalo, Capt Jerry

 

[Johnny Electron]

Hi Jerry, Please see attached.

 

[musicmanjer]

Johnny youre a Rockstar! Exactly what I needed!

Mahalo, Capt Jerry

 

[musicmanjer]

Aloha Johnny,

Ok I went through and checked resistance on the RRU. Center seems to be 960 ohms on one pair and 970 on the other. Pretty close. I checked Hard Port and Hard Starboard. They read 670 and 1310 respectively. These readings were made at the plug at the processor as to rule out an issue with wiring. I went ahead and reconnected everything and powered on the units. Still says error, so I went through the Rudder sensor setup again from Dockside Setup from scratch. It began reading the rudder and was able to do the Rudder center adjustment (+- 2 degrees). I did the Sea Trial and got the rudder limits set and will do another test to see if it indeed kept the settings held and will do a true sea trial on Monday with the unit. I will report back to my findings. It seems very strange that the processor lost the RRU functionality all of a sudden without any warning. We didn't have any variance in voltage that would cause a failure that I could notice. Have you known or seen any other units that behaved this way??

 

[Johnny Electron]

Tons of of things like EMI noise into the RRU cable can cause problems with the signal. Ensure that you are hard over when setting the port number and hard over the other way when setting the starboard number. Always set the center last.

 

[musicmanjer]

Ok I already did that in the order you suggested. EMI causes lots of issues and I am aware of that factor with other equipment. I have see VHF radio transmitting at 25 watts scramble all kinds of things, but I believe the cable from RRU is shielded which helps that issue. I will keep you posted on progress.
Thank you again.