"Molesworth" wrote in message
...
I have an ST4000 autohelm.

I call it 'Marvin' after the character in 'Hitchhikers Guide' as it has
a brain the size of a planet, but doesn't work.

The fluxgate compass is under the steps into the cabin, well away from
metal.

When Control Head is switched on the display reads 331deg, regardless of
which way I am heading.

If I turn it to anywhere else, it will show the reading I select but
perform the same anticlockwise turn, gradually getting tighter and
tighter turn, with the helm hard over till I get fed up and turn it off.

Looking at the troubleshooting guide, I have tried to re-calibrate the
compass by putting it into calibrate mode and turning slowly 360deg thro
3 mins to no avail. Makes no difference.

I tried the 'setup' pages in the manual, but when I try to follow the
illustrations of what should be displayed, it doesn't match. Leaving me
confused.

Anyone help me out here? Does the ST4000 have issues? Google doesn't
help at all.

Any input will be gratefully received.

Molesworth

Alm ost certainly a bad compass and yes, there are gimbals in the fluxgate
compass. Call Raytheon tech serbice and they can tell you how to test but
IMHO jsut by a new unit; about $150 if I recall having gone thru this with
my sportpilot +.

On Fri, 23 Mar 2007 13:29:07 -0500, Molesworth wrote:

I have an ST4000 autohelm.

I call it 'Marvin' after the character in 'Hitchhikers Guide' as it has
a brain the size of a planet, but doesn't work.

The fluxgate compass is under the steps into the cabin, well away from
metal.

When Control Head is switched on the display reads 331deg, regardless of
which way I am heading.


If this is the case, it's not "hooked up backwards", the problem is the
reading isn't changing (so the control turns more and more, waiting for
the heading to change...)

Might be the gimbals inside the compass (not the "head", the compass) are
stuck, but I had similar problems with mine and it was intermittent
connections of the cable between the compass and the head. Try wriggling
them a bit and see if the heading starts changing.

They use really tiny, non-standard connectors, but they are available if
you need to re-terminate.

druid
http://www.bcboatnet.org

On Fri, 23 Mar 2007 19:34:04 -0500, Molesworth
wrote:

In article . com,
" wrote:

...
When Control Head is switched on the display reads 331deg, regardless of
which way I am heading. ...

Try tapping it or moving it about somewhat vigorously. You need to
show it that you are in charge. Also the gimbals sometimes stick and
cause exactly the problem you are having.

-- Tom.

There are gimbals in the control head?

Molesworth

No, not in the control head, but in the fluxgate compass module.

When I first installed my autopilot, the fluxgate compass capsule
inside the housing had somehow got tangled up in the wiring so it was
held at a strange angle - gave _very_ peculiar readings.

I opened the compass housing and untangled things so that the compass
capsule was free to move - that fixed the problem.



--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

In article ,
druid wrote:

On Fri, 23 Mar 2007 13:29:07 -0500, Molesworth wrote:

I have an ST4000 autohelm.

I call it 'Marvin' after the character in 'Hitchhikers Guide' as it has
a brain the size of a planet, but doesn't work.

The fluxgate compass is under the steps into the cabin, well away from
metal.

When Control Head is switched on the display reads 331deg, regardless of
which way I am heading.


If this is the case, it's not "hooked up backwards", the problem is the
reading isn't changing (so the control turns more and more, waiting for
the heading to change...)

Might be the gimbals inside the compass (not the "head", the compass) are
stuck, but I had similar problems with mine and it was intermittent
connections of the cable between the compass and the head. Try wriggling
them a bit and see if the heading starts changing.

They use really tiny, non-standard connectors, but they are available if
you need to re-terminate.

druid
http://www.bcboatnet.org

Had a cursory look today at the fluxgate. I didn't have a teeny-tiny
phillips so all I did was shake it - and it rattled.

I shall take it apart and see if there is a tangling, what is causing
the rattle and also look at the connections to make sure they are making.

Cheers all for your valued input.

Molesworth

On Fri, 23 Mar 2007 13:29:07 -0500, Molesworth
wrote:

I have an ST4000 autohelm.

I call it 'Marvin' after the character in 'Hitchhikers Guide' as it has
a brain the size of a planet, but doesn't work.

The fluxgate compass is under the steps into the cabin, well away from
metal.

When Control Head is switched on the display reads 331deg, regardless of
which way I am heading.

If I turn it to anywhere else, it will show the reading I select but
perform the same anticlockwise turn, gradually getting tighter and
tighter turn, with the helm hard over till I get fed up and turn it off.

Looking at the troubleshooting guide, I have tried to re-calibrate the
compass by putting it into calibrate mode and turning slowly 360deg thro
3 mins to no avail. Makes no difference.

I tried the 'setup' pages in the manual, but when I try to follow the
illustrations of what should be displayed, it doesn't match. Leaving me
confused.

Anyone help me out here? Does the ST4000 have issues? Google doesn't
help at all.

Any input will be gratefully received.


A friend of mine bought an Autohelm in which the fluxgate compass was
internally wired back to front. That produced weird results.



Eric Stevens

"Molesworth" wrote in message
...
In article ,
druid wrote:

On Fri, 23 Mar 2007 13:29:07 -0500, Molesworth wrote:

I have an ST4000 autohelm.

I call it 'Marvin' after the character in 'Hitchhikers Guide' as it has
a brain the size of a planet, but doesn't work.

The fluxgate compass is under the steps into the cabin, well away from
metal.

When Control Head is switched on the display reads 331deg, regardless
of
which way I am heading.


If this is the case, it's not "hooked up backwards", the problem is the
reading isn't changing (so the control turns more and more, waiting for
the heading to change...)

Might be the gimbals inside the compass (not the "head", the compass) are
stuck, but I had similar problems with mine and it was intermittent
connections of the cable between the compass and the head. Try wriggling
them a bit and see if the heading starts changing.

They use really tiny, non-standard connectors, but they are available if
you need to re-terminate.

druid
http://www.bcboatnet.org

Had a cursory look today at the fluxgate. I didn't have a teeny-tiny
phillips so all I did was shake it - and it rattled.

I shall take it apart and see if there is a tangling, what is causing
the rattle and also look at the connections to make sure they are making.

Cheers all for your valued input.

Molesworth

As you will discover, the rattle is normal. Its just the coil wobbling
around on its gimbals. The wire that goes into the compass housing can foul
the gimbals if it get pushed too far into the housing. I believe there is a
tie that is supposed to prevent this but it could be loose.
The compass can be checked with an ohmmeter. Raymarine should be able to
give you the wire-to-wire resistances.
What sort of deviation does the control head indicate for the compass?

In article IXTNh.15493$__3.7268@edtnps90,
"Gordon Wedman" wrote:

"Molesworth" wrote in message

Had a cursory look today at the fluxgate. I didn't have a teeny-tiny
phillips so all I did was shake it - and it rattled.

I shall take it apart and see if there is a tangling, what is causing
the rattle and also look at the connections to make sure they are making.

Cheers all for your valued input.

Molesworth

What sort of deviation does the control head indicate for the compass?

Who can say? I can't get that far thro the menu's.

Thank you for the info on the fluxgate - I shall report back when I've
opened it.

Molesworth