ST60 Wind Transducer - What does this Test Show?

[RJV]

I've read all the threads on this issue, but I still have a question and am hoping someone can help.

I have two ST60+ Wind displays (mounted port and starboard) and suddenly both stopped showing wind direction and wind speed. On both displays the needle sits at the 12 o'clock position and the speed displays, variously, as "000" or "---".

I felt it highly unlikely to have 2 displays fail together but as one is a master and the other is a slave there is some interdependence, so I switched them over and reassigned the master/slave but this made no difference.

So then I went up the mast, removed the ST60 wind vane assembly, cleaned the 5 pin electrical plug and socket and reinstalled. This got it working correctly again for a few weeks .. on and off. But then same problem returned.

So I figured that maybe the pins on the end of the cable which connects the transducer to the mast head base might be corroded so I purchased and installed a new cable in the transducer (Part A28165, see photo below). This made no difference.

Today I accessed a junction box at the base of the mast to do some voltage checks according to test procedures supplied by Raymarine and posted many times on this forum. At the junction box I disconnected the blue, green and yellow wires coming from the ST60+ displays so only the red and shield remained connected through the junction box.

Using the shield as the reference point and measuring the wires which came down the mast:

- the red power wire measured 7.9 volts (which compares favourably with the specified 8 volts +/- 0.25 volts). To me this proved both power and ground wires up/down the mast were intact.
- the yellow wire measurement fluctuated between 2 and 4 volts (compares favourably against specified range of 0 to 5 volts). To me this proved that the wind speed transducer was sending a suitably variable speed signal down the mast.
- the blue wire measurement was fixed on 6.3 volts (exceeds the specified range of 2 to 6 volts). This is the port side directional element, and voltage should vary with wind direction changes.
- the green wire measurement was fixed at 0.7 volts (falls short of the specified range of 2 to 6 volts). This is the starboard side directional element, and voltage should vary with wind direction.

I believe the above results are telling me that the fault is at the top of the mast - with no variation in the voltage on the blue and green wires coming down the mast (even though the vane was observed swinging) the display needle has no reason to move, let alone display a correct wind direction. I believe this calls for a replacement of the small circuit board (Part A28164, see photo below) in the transducer to restore wind direction.

But the bit I can't make sense of is why the displays don't show any wind speed given that the voltage sent down the mast in the yellow wire is both variable and within the specified range?

If someone were to confidently assert that an out of range voltage reading from the port and/or starboard wind directional elements means that the wind speed is rendered inoperative then I would be more confident that replacing the small circuit board will restore both wind direction and wind speed. But just now this doesn't make sense to me - I can't see why the wind speed function would be dependent on the wind direction functioning.

The circuit board costs about $130 and I am capable of replacing it, but I do wonder if this will fix the whole problem, and not just restore wind direction but leave me without wind speed.

Can anyone shed further light on this please?

Thank you.

[senormechanico]

Damp salt in the masthead socket?
If you cleaned the plug on the masthead instrument and it worked for awhile, I suspect you were close to the solution.

[67Therapy]

I had an identical test. I did not change out my in-mast wiring. I took several trips up the mast to soak/clean the contacts with a contact cleaner over the course of a few days. I also brought the transducer down inside and throughly soak/cleaned it's contacts. I used a 2-part product called De-OxIT and then put it all back together with generous amounts of dielectric grease.
Been working for about 9 months since that "repair".
I hope you can bring yours back to life with a simple solution as well. I considered replacing the internals as you described, but I decided I didn't have the skill necessary (Couldn't figure out how to disassemble it without breaking it)...but fixing it sure beats buying a new one!

[belizesailor]

Good resource for troubleshooting Raymarine problems is theor tech forum at:

http://raymarine.ning.com/

[senormechanico]

I still suspect a leaky or bad connection at the masthead (or on the way up).
How about bad connection to the socket which is mounted at the masthead?
Your measurements at the bottom sound correct, but the displays seem to be telling you that they aren't getting any data.

Bet'cha problem is at the top.

[Therapy]

I had a similar problem when I had a boat.

I don't remember all the details on voltages but checked them at the mast base junction box according to the manual.

It ended up being a poor connection at the masthead plug. But that allowed enough moisture in the unit to ruin it. I replaced the masthead unit.

I did not learn that maybe the thing could be disassembled and cleaned/dried or that maybe just the circuit board could be replaces. I was told it could not be serviced and was sealed. Not sealed well enough at the plug end though huh?

Mine started as just an intermittent problem giving false direction at times. I was observant enough to note running down wind and it showing 50°. And then checking with the wife.

Short answer = masthead unit bad.

[RJV]

Thanks for the input - the consensus seems to support my view that the problem is at the top of the mast. I would truly like to believe its a poor connection/corrosion between the transducer arm and the transducer base mount.

However the 5 pin plug is new (it comes as part of the new transducer arm cable I installed) and I did my level best to clean the 5 pin socket in situ (my mast head is 63 feet above the deck). Also, there are 5 pins and clearly 4 out of the 5 - the red (power), shield (earth), yellow (wind speed) and blue (port direction element) - are all passing plenty of voltage which doesn't really support a poor connection/corrosion theory. Only the green (starboard direction element) is "strangling" the voltage, so this could potentially be a poor connection/corrosion.

But then if poor connection/corrosion was to blame I would have still thought that the voltage being passed down the blue and green wires would fluctuate with changes in direction of the wind vane ..... but it doesn't fluctuate. Blue is fixed at 6.3 volts and green is fixed at 0.7 volts, which leads me to believe the plug/socket electrical connection is good, and the cable down the mast is good .... and the problem is further back in the chain at the actual circuit board which converts the vane direction and anemometer spinning into the relevant electrical signals.

I suppose I could try cleaning yet again (it costs nothing, it's just really scary to do) but I'm not holding any hope that it fixes it.

I suspect the problem is the circuit board has malfunctioned and needs to be replaced - but I just find it so bizarre that I'm not getting a speed reading at the displays when the cable test shows correct voltage over the yellow wire. The only explanation I have is that Raymarine designed the displays to not display speed if the voltage over the two direction wires (blue or green) was under or over voltage. This would be a really stupid designing for this instrument.

I have attached one of my source documents and a link to another which might prove useful for others with similar problems.

http://www.videoacustic.com/sat/NO%2...0ser%20man.pdf

[Therapy]

Originally Posted by RJV

This would be a really stupid designing for this instrument.

Would not be their first.

Merry Christmas.

[senormechanico]

Thanks for the schematic.
After some study, I'm beginning to think it's a problem with the board in the transducer.
If you can open it up, look for moisture/salt, (90%) then possibly microscopically bad solder connections (10%), in that order.

[RJV]

Originally Posted by senormechanico

Thanks for the schematic.
After some study, I'm beginning to think it's a problem with the board in the transducer.
If you can open it up, look for moisture/salt, (90%) then possibly microscopically bad solder connections (10%), in that order.

Yes its easy to open up as I discovered. The top pod and bottom pod are simply screwed together (part 4 and 9 in the exploded view on page 4 of the attachment at my first post) and its just a matter of gripping both halves by hand and then turning them anti-clockwise - no tools required). The circuit board just drops in, no screws. I already had to split the pod and remove the circuit board in order to install the new cable which clips onto the underside of the board.

The photo of the board in the first post above is of my actual board. It looks in good shape - no signs of moisture or burning (although a microscope might reveal something). The pod halves screw together very firmly with an O-ring between and as the hood of the direction vane above generously covers the spindle axle which penetrates through the top pod I feel that it would be difficult or impossible for water to get onto the circuit board from above. The only way for the board to be effected by corrosion would be if moist air worked its way past the O-ring at the bottom to the arm, round past the cable socket and up the arm into the pod.

I'm thinking there is one more test I can still do. Since I committed myself to go up the mast to clean the socket one more time I can bring the transducer down and, on the bench, apply 8 volts DC across the red wire and shield, and then measure the voltages on the yellow, blue and green respectively. This test takes the mast head socket (possible corrosion?) and in mast wiring (possible corrosion, or short circuit?) out of the equation as I will be testing the transducer output directly at the 5 pin plug.

I think if I still get the same results (i.e. fixed 6.3 volts on the blue, and
fixed 0.7 volts on the green) whilst rotating the direction vane by hand this confirms absolutely that the circuit board is faulty. If I get different results (i.e. between 2 and 6 volts variable on the blue and the green), then the problem lies with the mast head socket or in mast wiring.

[RJV]

Originally Posted by RJV

I think if I still get the same results (i.e. fixed 6.3 volts on the blue, and fixed 0.7 volts on the green) whilst rotating the direction vane by hand this confirms absolutely that the circuit board is faulty. If I get different results (i.e. between 2 and 6 volts variable on the blue and the green), then the problem lies with the mast head socket or in mast wiring.

Well I scaled the mast today, again, removed the wind transducer and tested it on the bench. I get the same results for wind direction - fixed 6.3 volts on the blue, and fixed 0.7 volts on the green irrespective of which direction the vane points - but strangely enough slightly different results on the wind speed - voltage between 0.08 and about 0.50 volts on the yellow.

Whilst I can't understand why I would get a lower voltage on yellow on the bench as compared to at the junction box (when the transducer was installed on the mast) I'm pretty convinced by the bench test results for the blue and green that the circuit board is faulty in respect to wind direction and I'm poised to order a new board. One possible, but unlikely, explanation for the different results at the junction box could be a voltage leak (short circuit) in the in-mast cable or at the mast head base between the red or blue (which measured 7.9 and 6.3 volts respectively) across to the yellow. Now that the wind transducer is removed I will use an ohmeter at the junction box to confirm whether the resistance between all possible pairs of the five wires running up the mast is infinite (i.e. no short circuits). Hopefully I won't discover a low resistance between the red and yellow, or between the blue and yellow.

[RJV]

Originally Posted by RJV

Now that the wind transducer is removed I will use an ohmeter at the junction box to confirm whether the resistance between all possible pairs of the five wires running up the mast is infinite (i.e. no short circuits). Hopefully I won't discover a low resistance between the red and yellow, or between the blue and yellow.

Just completed this test and there are no short circuits between any pairs of the 5 wires, nor are any shorted to the mast. This rules out a short circuit in the mast wiring and at the mast head base. It doesn't rule out a poor connection on the green but as I got the same result (particularly on green) in the bench test I think its safe to assume that the 5 pin plug to socket connection is good on all 5 pins. Therefore, the changed voltage reading on yellow (wind speed) on the bench test versus at the junction box is a mystery.

In any event the circuit board is not producing the correct output for wind direction so I will purchase and install a new circuit board (costs about $130) and hope that this restores both wind direction and wind speed to my displays.

Earlier I commented that it would be a really stupid design to not display the wind speed if the voltage over the two direction wires was under or over the specified voltage. I suppose Raymarine could justify this on the basis that "if the wind direction cannot be determined due to a fault then we have designed the display to suppress showing any wind speed even though this information is available, as to display the speed with an incorrect direction would hide a fault and also mislead the skipper". I could accept this position if the Raymarine documentation was more helpful and explained this sort of thing. But Raymarine doesn't - its customers have to spend precious leisure hours trying to figure things out for themselves and put themselves at risk climbing 63 foot masts time and again. And that really, really annoys me.

Raymarine must have been asked about this problem thousands of times, and it would be well placed to document the various scenarios so that we don't have to keep guessing and climbing masts.

[DotDun]

Originally Posted by RJV

Earlier I commented that it would be a really stupid design to not display the wind speed if the voltage over the two direction wires was under or over the specified voltage. I suppose Raymarine could justify this on the basis that "if the wind direction cannot be determined due to a fault then we have designed the display to suppress showing any wind speed even though this information is available, as to display the speed with an incorrect direction would hide a fault and also mislead the skipper". I could accept this position if the Raymarine documentation was more helpful and explained this sort of thing. But Raymarine doesn't - its customers have to spend precious leisure hours trying to figure things out for themselves and put themselves at risk climbing 63 foot masts time and again. And that really, really annoys me.

Raymarine must have been asked about this problem thousands of times, and it would be well placed to document the various scenarios so that we don't have to keep guessing and climbing masts.

FWIW, RM has the same design with the ITC-5 - Analog Transducer to STng/NMEA2000 Converter. I found with this device if the temperature part of a speed/temp transducer is broken (as they all are after 2 years), the ITC-5 refuses to use/show the speed data from the same transducer (even though they are completely separate circuits). Apparently the engineers decided if the temperature is broken, they can't trust the speed information. IMO - stupid! The fix is to disconnect the temp leads from the transducer and place a 10k ohm resistor on the ITC-5 temp connectors, then it'll be dumb, fat, and happy displaying 77 degrees f.

[senormechanico]

RJV,

Look at the schematic in the upper left hand corner.
The +8 volt supply has two branches, +8V and +8_PRT (TP32 and TP4).
What's going on at TP4?

[RJV]

Originally Posted by senormechanico

RJV,

Look at the schematic in the upper left hand corner.
The +8 volt supply has two branches, +8V and +8_PRT (TP32 and TP4).
What's going on at TP4?

Thanks for your continued interest.

Electronics at the schematic level are not my strong point, but here is some guess work.

I think the power module (top left schematic) supplies two power "types", to the rest of the PCB - both 8 volts but the second one, +8V_PRT, has some sort of added protection and stabilisation through the addition of series diode D1 and parallel capacitor C8. This second power supply feeds uniquely to the Vane Sensor module (top of middle left schematic) which module is then linked to the port and starboard "Buffer" modules through "X" and "Y". I note that parts of the Vane Sensor and Buffer modules are also supplied by the first +8V power supply.

The Anemometer module, however, is supplied only by the second power supply, +8V, and this module doesn't appear to have any linkages to other modules other than a shared shield (0V, 0VA). I guess this could explain why, at the transducer, the wind speed signal appears to be OK with variable output voltage over the yellow wire even though I am getting (faulty) fixed output voltage over the wind direction modules (blue and green). Given there are two Buffer modules and both appear to have turned faulty, I would deduce that the fault lies somewhere in the Vane Sensor module which is common to port and starboard - it could be an open or short circuit, it could also be a failure in IC4 which is the brains of the module .... it converts changes in a magnetic field (moving wind vane) into changed voltage output through the two Buffer modules.

Not sure if this gets me closer to the solution.