B&G wierdness

Pelle

Pelle

Anarchist
744
39
Göteborg, Sweden
I was guest naviguesser on an X-35 last week and encountered a wierd problem with the B&G instruments. The boat had an H2000 Hercules system (I think it was an performance processor but not really sure and I did not have time look att all the boxes) Most things workede but the AWA (and measured WA) behaved in avery strange way. Upwind in light but steady air the AWA showed 16 deg on SB and 23 on Port. I think the values are a bit small but the difference could be a small offset and a bit of wind shear. Downwind however the AWA read 46-50 degrees while sailing att approximately 140 AWA. The vane on the masthead unit is physically pointing in the right direction but the AWA does never read more then 60 deg...Have anyone encountered a similar problem? Any ideas was the cause might be?

 
Moonduster

Moonduster

Super Anarchist
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A messed up MHU offset calibration value could explain the upwind results but doesn't explain the off-the-wind issues.

My first guess is wiring, second guess is mast head unit. Check all the connections. There are at least three - at the processor, at the mast junction box and at the mast head.

Good luck!

 
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GnarlyItWas

GnarlyItWas

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Little PCB inside the masthead unit, could be the wiring or the processor but the first choice the the masthead unit PCB. Betcha a pint it's that.

It's called a 213 pcb

 
Sparky

Sparky

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Greater downtown Tasmania
We had this happen twice with Hydra 2000 instruments.

In both cases it was the connector at the top of the mast that the wand plugs into.

Had to be replaced due to corrosion of contacts.

 
LeCanard

LeCanard

Quack, quack, quack…
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Retired-No Money, no hurry, no worry
If you're i G-burg, I suggest you either contact Sportmanship Marin or Ramantenn. The former are the B&G agents that has little or no knowledge about things. The latter are the blokes that knows stuff but have no really interest working with them, so there might be some persuation to done there.

/LC

 
Pelle

Pelle

Anarchist
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Göteborg, Sweden
Thanks guys....i know the folks both at Sportsmanship and Ramantenn but everyone is on holiday in Sweden in July so asking here was a lot quicker... :)

 
F

Ferret

Member
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Singapore
The team I naviguess for has in the past had a B&G agent as tactician... often 'just happened' to have a spare masthead circuit board or two in his kit bag that we could swap in if needed. Seems to be a be bit of an achilles heel.

 
NyJboat

NyJboat

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Ferret said:
The team I naviguess for has in the past had a B&G agent as tactician... often 'just happened' to have a spare masthead circuit board or two in his kit bag that we could swap in if needed. Seems to be a be bit of an achilles heel.
Click to expand...
They hate any kind of electrical discharge. The boat I sail on has one of the tallest rigs in the harbor and we usually go through 1 per year from lighting strikes nearby, not even direct hits. The bad news is they cost about $500 USD if I recall right. The good news is the old one can usually be refurbished so that you have a spare.

 
LeCanard

LeCanard

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Retired-No Money, no hurry, no worry
If you have the old 213 PCB ASSY (213-10-005) type with a pick-upcoil for the windspeed at the bottom here is how you do it yourself. It takes some skills and I admitt that doing this at the mast head isnt the easiest thing to do.

1) Replace both the FET transistors (BF256A).

2) Connect two multimeters to the mast cable. Refer to red cable so that one is between red and green, the other between red and blue.

3) Adjust the trim potentiometers so that both multimeter readouts are so close to zero volts as possible....

Somewhere between 0 and 10mV is acceptable. The two pots are affecting both phases when trimmed, therefore its best to use double multimeters.

4) Refit the top cap with boss, skirt and vane. Check if the instruments are reading out a balanced value, same on each tack.

5) Repeat 3 and 4 until youre satisfied or wake up a B&G agent from his hammok.

And yes, I used to bring with me a few of those PCB's too when i was racing (along with finunits or paddlewheels).

/LC

 
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D

davidminors

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Its worth knowing that all B&G MHus supplied in the past 3 years or so have a new PCB design which much improves its vulnerability to static discharge etc. These sorts of issues are much much less likely to occur.

Also note that the Measured wind angle fro the B&G MHU is made up of 3 analogue signals from the red, green and blue wires. If any one of these drop out due to damaged cable, connector etc. then you will see strange wind angle readings

 
P

perfectten

New member
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Nieuwpoort Belgium
DavidMNZ said:
Its worth knowing that all B&G MHus supplied in the past 3 years or so have a new PCB design which much improves its vulnerability to static discharge etc. These sorts of issues are much much less likely to occur.

Also note that the Measured wind angle fro the B&G MHU is made up of 3 analogue signals from the red, green and blue wires. If any one of these drop out due to damaged cable, connector etc. then you will see strange wind angle readings
Click to expand...
Hi,

On our X-35 we have a vertical MHU.

the AWA & TWA are no longer reliable and correct, so diagnose : PCB broken.

Today, I was lifted again in the mast after the technician changed the PCB.

When I connected the cable, there was no windspeed available, and the windangle was 180° wrong.

So again with MHU downd and back to the technician.

Also printed an instruction by B&G regarding how to replace the PCB.

I hand it over to the technician and I hope he made a mistake in the connection.

Does anyone recognize the symptoms ? so no windspeed and AWA is 180° wrong.

regards.

Peter

 
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