On May 21, 7:43*am, Big Al wrote:
I have a ST4000 tiller pilot which came with a recently purchased
yacht.

So the unit may never have been installed correctly. Which I means you
may need to check that the fluxgate compass that supplies the heading
data to the head unit is sited correctly (ie no ferric metal within 1
metre).

The compass reading is wildly out, and I wanted to calibrate the unit.

I assume you've swung the vessel and checked the ST4000 compass
reading against a hand compass or a steering compass. Raymarine
suggests you resite the fluxgate compass if the two compass readings
differ by 15 degrees. On my unit (now 8 years old), the readings are
only out by a few degrees.

However, I cannot start the calibration process. Pressing and holding
'standby' does not enter calibration mode, and after 10 seconds of
pressing 'standby', the unit displays 'P12'.

Doesn't the ST4000 have three types of calibration: standard user
calibration; dealer calibration, and compass calibration (aka
automatic compass deviation correction)?

Standard user calibration (access to the 11 or 12 calibration levels
that start with Rudder gain and Rudder offset) mode is started by
pressing and holding standby for 5 seconds.

Dealer calibration mode is, I think, only described in the older
Operation and Installation manuals (and I think it's not in the more
recent O & I manuals). My O & I manual is on board (and I'm not on
board at the moment), so I cannot describe it today.

Compass calibration is started by pressing and holding standby for 1
second, following by pressing Auto (to get past the - - CAL display
used when turning the boat in a circle for 3 minutes to let the unit
automatically sense and set magnetic deviation), then pressing +1 or
-1 changes the compass heading reading.

I have checked that calibration has not been locked out.

You did that by pressing and holding down Standby and -1 for 10
seconds, right? You should then see CAL ON. Turning to CAL OFF stops
access to the standard user calibration page (where you set Rudder
gain, Rudder offset etc).

Have you worked through the standard calibration menu? Might be worth
checking Calibration Level 9 (local magnetic variation) to see if it's
set to a bizarre number or to west instead of east (or vice versa).
You can turn OFF local magnetic variation until you have the compass
function working.

Has anyone else come across this problem. In all other respects the
unit works well holding course, etc.

I've not met your problem. My ST4000 (the ST4000+ GP tiller model, the
+ and GP referring to a slightly higher rating of the linear drive and
a couple of parts of the drive unit are made of metal instead of
plastic) has been put to tough work for 8 years, including tens of
thousands of miles of blue water cruising. I've replaced the linear
drive unit once and the head unit once (starting to sound like great
grandfather's axe, no?).

My unit has problems dealing with strong tidal currents when close
inshore - so I hand steer in those situations. I particularly use my
ST4000 in track mode (steering on a line between two GPS waypoints)
and auto mode and have been quite happy. I've been less happy with
wind trim mode (I prefer a mechanical wind vane self steering device
for that).

Cheers