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