ST4000 tiller autohelm wild over correction

[hertfordnc]

Subject autohelm has worked perfectly on my 1977 Nich 31.

Saturday I turned it on and it went into a slalom.

Any guesses where to start looking for trouble? I probably won't replace this anytime soon (adopting a child) and the system is dated so I will probably just look for components on ebay if I can't find something to fix (wiring?)

thanks

[hertfordnc]

it looks like a lot of good answers are posted above- same problem, same autopilot, same weekend-

thanks

[HerbDB]

You might also try resetting everything to factory defaults. Some stray electrons may have changed the response settings.

If that doesn't work, check the compass heading sensor and its wiring. Erratic heading inputs can give your the type of behavior you are experiencing.

[autopilotos]

Hello,
Check if there are no magnetic materials ,like magnets,speakers,ventilators(some swinging ventilators have shown influencating the fluxgate compass)near the compass .
Or perform new setup of the system as in the manual.

jean

[kymatthegulf]

Hello, I spent hours on my tiller helm ( autohelm200) resetting etc and it still gave up occasionally or went into slalom mode. Eventually I used "contact cleaner on all the wires and connections and opened up the case and very carefull dismantled the unit . opened the touch buttons and cleaned them, reassembled with silicone grease . wow it worked a treat. Phew saved lots but took 10 to 15 hours patient work.

[hertfordnc]

mine "fixed itself" but looking over this thread I suspect it had to do with the contacts.

After the above replies I returned to test it and it worked fine. I can only assume the problem was in the connector in the cockpit having not done anything to any of the wiring.