autohelm st4000 phantom dodge

[hornby sailor]

my st 4000 will occasionally veer to port about 20 degrees and then correct back to it's heading. a friend gave me another unit that had been replaced because it would turn 360 on its own. what is going on? its not anything being moved near the flux compass.

[senormechanico]

Mine was caused by 8 or 9 bad solder connections to the four 3 Mosfet transistors in the head unit.
Easy solder fix.

[giant]

Maybe try re calibrate your flux-gate compass.

Requires some button pressing and a 360 degree circle... see your manual.