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Old Nexus Silva wind instrument problem


Notquitecapnron

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I have what appears to me to be 80's era Silva Nexus multi control instrument and server. It has worked fine for the two years I have owned my Laser 28. End of last season, the wind instrument stopped working on starboard tacks. On port tacks everything read correctly. I thought perhaps something with mast stress was causing a wiring issue. Boat is on the hard right now, same problem. I can watch the instrument atop the mast...it looks like it is working fine, but only reads on the displays when pointing port of center. I have rewired connection at mast base....same problem. I pulled, and reinserted wind instrument wires at the panel...same problem. Any ideas?

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If as you say you have checked the connections from the transducer to the server, including the four prong plug, then almost certainly your transducer has partially failed, in a somewhat unusual manner.

 

I assume you have multiple inputs and multiple instruments hooked to a common server. I also assume that you are not getting any wind reading on any of the instruments when the wind is on starboard. Are these correct assumptions?

 

If so, then it has to be either the transducer or server output. Put a multimeter on the output wire (assume the green and white wires if it is as you describe a 80's server - a Nexus Classic) at the server wind input to see if you are getting any output from the transducer when the wind is from starboard. (The reading does not matter, just that there is output) If not, it would strongly suggest you have a transducer issue, and then you need to either replace or rebuild the transducer, if as you say you have checked all the connections. Probably only able to replace, have had no luck finding anyone to rebuild the old wind transducer. Garmin makes a new transducer, but its NMEA 2000, so you need a converter cable from 6 to 4 wire, which they have. If you have output to the server, then put the multimeter on the server output (if you have other transducers connected, disconnect them - just disconnect the green wire)

 

If you have output from the server, (which is hard to imagine given the daisy chain nature of the display connections) then check the connections between the first instrument and the server. Again assuming that the first instrument is not showing wind data on starboard. But this is desperation time. Cannot imagine how that could be - that it displays some data but not wind data when on starboard. For the life of me I cannot see how that could happen.

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If as you say you have checked the connections from the transducer to the server, including the four prong plug, then almost certainly your transducer has partially failed, in a somewhat unusual manner.

For testing purposes, I actually eliminated the four prong plug and direct wired that connection a the mast base. No change.

 

 

I assume you have multiple inputs and multiple instruments hooked to a common server. I also assume that you are not getting any wind reading on any of the instruments when the wind is on starboard. Are these correct assumptions?

Correct. Three displays...all work fine on port. ----- on starboard.

 

I will check output as you suggest. You have the wire colors correct, so I am confident we are talking about the same system.

 

Thanks

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I ended up having to replace my original Silva wind transducer after around 25 years. It was showing similar symptoms to yours. I replaced it with the wired NX2 wind transducer w/o cable. It connected directly to the old cable and to the Classic server. I now have a Classic server running NX2 multi's, NX2 wind gear, NX2 log/temp and original Silva depth transducer.

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I have what appears to me to be 80's era Silva Nexus multi control instrument and server. It has worked fine for the two years I have owned my Laser 28. End of last season, the wind instrument stopped working on starboard tacks. On port tacks everything read correctly. I thought perhaps something with mast stress was causing a wiring issue. Boat is on the hard right now, same problem. I can watch the instrument atop the mast...it looks like it is working fine, but only reads on the displays when pointing port of center. I have rewired connection at mast base....same problem. I pulled, and reinserted wind instrument wires at the panel...same problem. Any ideas?

Wind transducer is dead. If it is a wiring problem you would not get a reading at all no matter the direction. It is probably tough to find a replacement as that version is a number of years out of production (only place I could think of is Chicago marine electronics and Achilles is a great guy who will always help you out) but as mentioned above - some of the newer models will work too

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The Nexus wind sensor is rather special. It has a ball with special black and white pattern and the colour is read with two opto sensors. Since you get some readings, at least one of the opto sensors is working. The problem may be dirty or otherwise discoloured (or broken) ball or dirty/broken/displaced opto sensors. You should see PWM data on both channels when the propeller is rotating. The frequency is 3.4 Hz * (wind speed in m/s +0.3) and the duty cycle is 20-80% depending on AWA.

 

The output is open collector requiring a pull-up (in the server). Thus without the wind sensor connected, the input in the server should be high and with it it should be a square wave with frequency changing with wind speed and duty cycle with AWA.

 

For these errors the service manual suggests replacing the nosecone (new ball), adjust the opto sensors (if displaced) or replace the PCB.The opto sensors need to 1-1.5 mm from the ball and not touch anything. This can be checked by remowing the vane (not the propeller). The vane should be reinstalled with a new gasket or silicon glue.

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Looks like some good info, but flying over my head as well as beyond my abilities and ambition to rebuild. I will try cleaning it....that's easy enough once it's on the deck again. Does anyone know exact Garmin replacement transducer that works with Silva Nexus?

 

Thanks for all the ideas.

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You can check the LEDs flashing in the server. There is a separate LED for both of these two signals. Both LEDs should flash once each turn of the propeller. Here is the server manual: http://www.nexusmarine.se/wp-content/uploads/2011/11/Server-Man.pdf

 

The old wind sensor you have is connected to the special wind input in the server. Newer model (gWind and wireless) are connected to the Nexus bus (can be connected to the server or any display). I don't know if old servers can work with wind data in the Nexus bus, but at least you would get AWA and AWS on the displays. But they do work with NMEA 0183 wind data, thus you could use any wind sensors with NMEA output.

 

Here is the gWind Installation manual: http://static.garmin.com/pumac/gWind_Install_ML.pdf

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Joakim,

 

I've never noticed any led's flashing in the server, but then again, I don't look in there in the dark. I'm skeptical that I have any led lights in this server, but I will check. My server is definitely a generation or two behind the manual you suggest. I have the operating manual. It reads "Silva Nexus" on the front. I'll check out the gWind. Just not sure I want to spend more money on the current aged system.

 

I'm comparing feasibility and cost involved with moving to a vYacht multiplexer for everything except the wind. For wind, I'm experimenting with a Sailtimer vane. All sending to iRegatta or nav app on iPad 4th generation. The sun/glare on iPad is a real issue however.

 

Thanks again for the info.

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Joakim,

 

I've never noticed any led's flashing in the server, but then again, I don't look in there in the dark. I'm skeptical that I have any led lights in this server, but I will check. My server is definitely a generation or two behind the manual you suggest. I have the operating manual. It reads "Silva Nexus" on the front. I'll check out the gWind. Just not sure I want to spend more money on the current aged system.

 

I'm comparing feasibility and cost involved with moving to a vYacht multiplexer for everything except the wind. For wind, I'm experimenting with a Sailtimer vane. All sending to iRegatta or nav app on iPad 4th generation. The sun/glare on iPad is a real issue however.

 

Thanks again for the info.

 

There are no LED's on a classic server, just the more recent servers. As for the Garmin replacement it is the Gwind, and they have a converter cable that converts the output from the Gwind from 6 prong to 4 prong so you can hook the unit to your existing wire.

 

Our depth transducer died a bit ago and the new transducers were not compatible with the classic server so upgraded the server and got a new depth transducer included in the package. We have had the Nexus system for 14 years now, have had to replace the depth, wind (lightening hit it), and GPS transducers, and as mentioned we replaced the server. We have a navigator and multi display below deck, and two multi displays above deck. We have a multiplexer on our AIS (displayed on an MFD, which also connects to the autopilot) and have connected the Nexus server, via nmea 0183, so we can have the autopilot steer to the wind - do not use it much, but when we have it was good. What I like about the Nexus system is the ability to display any of the information so I can change from navigation (sog/cog or btw/dtw) and wind (speed/direction), to navigation or wind on one display, and sog/depth on the other.

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From Nexus....

 

If this is the old single rear fin / two bladed propeller type wind transducer, then I suspect the nose cone bearing is failing which would necessitate a replacement. If I may ask, where are you located? There are a few dealers out there that can still bench test these for you to at least verify a failure prior to replacing.


If it comes to a replacement, the following will be your target:

gWind™ Transducer


With an adapter, you could utilize your existing mast cable. Note that when installing this transducer, it will actually need to be moved from the Wind port of the server and placed on the BUS RS 485 port instead.

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If there are no LEDs, you can use a multimeter to measure the voltage between ground and the the inputs. You should see the voltage going up and down (from close to zero to probably close to 12 V) when rotating slowly.

 

So they think that the bearing is so shot, that the opto sensors are too far from the ball?

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