Triton MFD Failures

[DragonflyBob]

Just sharing to see if anyone else has had this experience.

On our 2016 Dragonfly 32, we have a factory installed B&G system that consists of binnacle mounted Zeus 2 Chartplotter with three (3) slaved Triton MFD units. Top of the mast receives wind data via a WS320 unit. Speed and depth data are through Airmar transducer. Also on the network providing AIS data to the chartplotter is a B&G VHF. Since we bought the boat last September, the system had worked flawlessly.

Two weeks ago, the speed and depth data went away, just blank bars on the MFD’s. I pulled the transducer out and checked to be sure there was nothing obvious. Decided to order a new one and replaced it with a DST 810 that I spliced into the system (per another thread I started here). When I cut the cable I checked the power leads to the previous transducer and got 13v. Installed the new one and same result on the MFD’s but at least DST810 communicated with my phone via the Airmar Cast app. At this point, I planned to have an electronics tech come troubleshoot the system but I had to wait a week as we had an offshore race to sail.

Morning of the offshore race, one of my crew comes on board and I show him what is happening. He goes in the instrument settings of the Zeus 2 via its menus and finds the DST810 is seen but not turned “on”. He changes the setting and the speed and depth data comes back. Happy Days!

Well not for long. About an hour later, the speed and depth data goes back to blank bars again and we can’t get the Zeus to see the transducer. We decide there’s some kind of network gremlin at play and sail our race. But also disconcerting is that my phone via the Cast app is no longer seeing the Airmar DST810. We finish the race at the finish location and my wife and I get up the next morning to start the delivery trip home. We power up the instruments and now all three MFD’s are completely dead, black screens. We can still power up the Zeus 2 and it works fine except obviously we have no speed, depth, or wind data so no autopilot.

At this point, my plan is still to get a marine electronics tech on board to troubleshoot. My experience with NMEA 2000 networks in terms of troubleshooting is nil so hopefully this can be diagnosed relatively easily.

Just sharing and if you have had or seen similar failure or chain of events, would appreciate what resolution you pursued or any opinions.

[George_SD]

N2K networks are not that complex. There are a few simple rules to follow on termination (network edges) and supplying power, but otherwise they are not too difficult. If you are seeing these problems all of a sudden with multiple devices - I would suspect power distribution (there is no reason for multiple MFDs would stop working at the exact same time). Good call on getting an electronics person to troubleshoot this.

[SailingHarmonie]

Always start with the easy wins...

If the screens are blank, I agree with GeorgeSD, find the power feed into the NMEA network. Be sure the connections are clean and good. Don't forget to check the fuse holder. They frequently corrode internally if they get wet.

[Statistical]

Another troubleshooting step is you should be able to get the chartplotter to show depth and speed (STW). If it can then the issue isn't the instrument. The data is being put on the network the MFD are just not showing it for some reason. If it can't then the data isn't being put on the network which is why the displays are showing no data.

It doesn't give you the exact answer but it does narrow does the problem
1) The insturments themselves (to include any related power/wiring issues)
2) The MFD (to include any wiring/power)

[DragonflyBob]

Originally Posted by SailingHarmonie

Always start with the easy wins...

If the screens are blank, I agree with GeorgeSD, find the power feed into the NMEA network. Be sure the connections are clean and good. Don't forget to check the fuse holder. They frequently corrode internally if they get wet.

But I am assuming the Zeus also gets its power from the network 12V power feed so if it is coming on, I would have to assume the power feed to the network is fine.

Just to clarify, the issue started out with all three MFD’s coming on and still giving us wind and chartplotter data but no boatspeed or depth (just blank bars). It evolved to fully blank/black displays when the system is turned on.

[DragonflyBob]

Originally Posted by Statistical

Another troubleshooting step is you should be able to get the chartplotter to show depth and speed (STW). If it can then the issue isn't the instrument. The data is being put on the network the MFD are just not showing it for some reason. If it can't then the data isn't being put on the network which is why the displays are showing no data.

It doesn't give you the exact answer but it does narrow does the problem
1) The insturments themselves (to include any related power/wiring issues)
2) The MFD (to include any wiring/power)

The Zeus chartplotter is currently not showing any boatspeed or depth data that would come from the Airmar transducer. It only gives us COG and SOG data because its GPS is functional. The Autopilot option is not available also on the Zeus chartplotter and I am assuming at this time this is because it cannot get boatspeed and wind speed/direction data.

Again, the Zeus chartplotter is coming on fine and I am assuming it shares the same 12V power feed on the network with the three Triton MFD’s which is why it is so strange that the MFD’s are all showing black screens at this time.

Thanks for the reply and interest!

[Kelkara]

Originally Posted by DragonflyBob

But I am assuming the Zeus also gets its power from the network 12V power feed so if it is coming on, I would have to assume the power feed to the network is fine.

No. The zeus will have its own 12V power coming in separately to a different connector on the back. It will not draw the power for its own operation from the n2k network.

[Statistical]

Originally Posted by DragonflyBob

The Zeus chartplotter is currently not showing any boatspeed or depth data that would come from the Airmar transducer. It only gives us COG and SOG data because its GPS is functional. The Autopilot option is not available also on the Zeus chartplotter and I am assuming at this time this is because it cannot get boatspeed and wind speed/direction data.

Again, the Zeus chartplotter is coming on fine and I am assuming it shares the same 12V power feed on the network with the three Triton MFD’s which is why it is so strange that the MFD’s are all showing black screens at this time.

Thanks for the reply and interest!

Chartplotters and autopilot computer due to the higher power requirements are normally powered independently of the N2K bus so they use the bus for data only. MFDs (and instruments) are usually bus powered so use the bus for both power & data. Not universal but that is the most common configuration.

I thought the MFD were coming up just not showing any data. The fact that they aren't and you have no STW on the network (not showing on chartplotter) would mean the other suggestions to verify N2K network power are on point. Bad power on the N2K network would explain both MFD not working and transducer not putting any data on the network.

[DragonflyBob]

Originally Posted by Kelkara

No. The zeus will have its own 12V power coming in separately to a different connector on the back. It will not draw the power for its own operation from the n2k network.

Originally Posted by Statistical

Chartplotters and autopilot computer due to the higher power requirements are normally powered independently of the N2K bus so they use the bus for data only. MFDs (and instruments) are usually bus powered so use the bus for both power & data. Not universal but that is the most common configuration.

I thought the MFD were coming up just not showing any data. The fact that they aren't and you have no STW on the network (not showing on chartplotter) would mean the other suggestions to verify N2K network power are on point. Bad power on the N2K network would explain both MFD not working and transducer not putting any data on the network.

OK, I understand now that the Zeus chartplotter and the autopilot computer (AC42N) have their own separate 12V power supplies and the sensors on the network (wind, speed/depth, rudder feedback) get their power from the 12V feed to the network. The boat has one (1) main “Instrument” toggle switch on the boat’s main panel that allows the whole system to be powered up but down below in the aft cabin there are separate circuit breakers for the chartplotter and autopilot. Since the MFD’s are not powering up nor am I getting any data from the wind and speed/depth transducers (and I have to assume the rudder feedback sensor is not getting power), I’ll try to see if the network power supply was set up with the recommended 5 amp fuse and see if I can find it verify its condition. That could be an easy fix but there is always the question of why that fuse blew in the first place if it is the issue. I’ll still need to get a marine electronics tech.

Thanks again!

[Jammer]

First thing to check is the splice to the DST800 since it is new. Perhaps power and ground are shorted there if the splice was performed in an expedient manner.

Otherwise the full troubleshooting procedure is to follow the 12v power starting at the power injector. If you have a short and are blowing breakers/fuses then disconnect parts of the network until you get a portion that is functional, and re-add things one at a time. Otherwise use a DMM to confirm that there is power on both sides of the power injector and work out from there.

[George_SD]

Something to keep in mind is that since the bus/network feeds power so some devices, you must ensure there is enough power provided for all devices. It's possible that if the network is not designed correctly, there is not enough power or it is provided at the wrong location that causes voltage drops on the edges.

Here is an example of an improperly designed network