It may not be the autopilot. I assume, because you declared no other reference, that reference is your fluxgate compass. You must
first determine if the problem is coming from the autopilot or the compass. The easiest way is to swap out the compass and see if
the problem returns. However, you should review the compass's location on the boat and make certain it isn't close to other
magnetic fields. Also it would be helpful, when this next occurs, to reverse your track and sail the identical path again to see
if you can reproduce the problem relative to the boats position and track. This problem is not uncommon and provides incentive to
use a Satellite Compass.
Steve

"Paul" wrote in message ...
I am having an intermittant, but serious problem with my ST7000
autopilot.

At very random times, in either standby, auto, or track, the AP will
go nuts - wheel goes hard port all the way, and I can't override it,
and displays 'MANUAL' on the display! To fix it, I hit 'standby' to
regain control of the boat.

I thought the 'manual' setting was to be able to override the steering
from auto in an emergency. This setting is 'off' now.

There seems to be no consistancy when it happens.

Not sure if this is an environmental issue, ie stray energy from
radar, etc from other boats, land based communications, etc. two times
it happened in the Cape Cod Canal, which has a lot of high power
stations. Was just a wild guess. But it has happened in open water as
well.

The electronics system on board has a NMEA fluxgate compass (not the
original), Lowance chartplotter/gps, AIS receiver, tridata
instruments, feeding into a Brookhouse multiplexer. Not overly
complicated. I also have a SPOT satellite messenger on board. Not sure
if that could cause issues.

But it is disconcerning that I lose total control at random times.

Overall it is working great, other than these random emergencies!

Any help would be great