ST 60 Strange heading fault

[KAM]

Just sailing along on autopilot and I noticed the fluxgate heading indicator reading was stuck. It's a full ST60 set up with ST4000+ autopilot. Did all the usual checks on connections no magnets near the fluxgate head. Powering off and on it worked normally for 10 seconds then stuck each time. Tried this about 6 times. An hour later it's all normal again. Worried about the fluxgate compass. Anyone got any experience with these. Anyone else experienced these symptoms and have any pointers.

 

[Yngmar]

Ours did a similar thing and upon taking it apart, the needle bearings that keep gimballing the unit were stuck mechanically. I cleaned them up, applied some lubricant and it's been fine since (2.5 years ago I think). Have a peek inside.

To open the unit (black little dome), remove it from the wall and undo the screws on the underside. It looks like the dome cap screws off, but that's misleading!

 

[KAM]

Fantastic thanks very much. It was a long shot posting about an intermittent fault but that would explain the symptoms.

 

[KAM]

Just had a look. No needle bearings in mine simple bearings with a big mass. It's not possible for a stuck gimballing mechanism to cause a heading jam.

 

[jwilson]

I had similar, changed fluxgate compass, no more problems.

 

[KAM]

Not much to go wrong. The weak link is probably the flexible pcb connector inside the unit.