[DG] [DG11] Autopilot disengaging - S1G with ST6002 control head

[umuk]

We recently got a problem with our Autopilot (S1G with ST6002 control head driving a Lewmar Integra Drive Unit) disengaging silently from Auto to Standby.
No alarm raised, no beep, no message - just goes to Standby.
Autopilot can be immediately reengaged and then runs hours (or days) at end.

There is no pattern how long after power on or running in Auto this happens. Also no relation to load caused by sea state or wind strength.
We crossed the Atlantic with it 5 months ago and it sometimes kept going for 3-4 days without disengaging sometimes just a few hours. Issue still persists with now only shorter daysailing trips.

Any ideas ?

[Derek - Raymarine - Moderator]

Hi Umuk,

Thankyou for your enquiry.

The usual cause of the autopilot dropping back to STANDBY is power supply and often triggered by a momentary drop in voltage.

This can be triggered by many things, not only the cabling and wiring to the autopilot itself, but also other equipment onboard starting and stopping.

You will find this link usefull too.

Regards
Derek

[umuk]

Hi Derek,
took a while to make a thorough check and test.
I ran a data logger to monitor Battery Voltage, Voltage and Current to the AP drive, Current to Fridge (as the only additional "serious" power consumer that might cause spikes/drops).
The events when the Autopilot disengages seem not related to power issues. It also happens with Battery voltage continously >13.5V, Fridge compressor not running or starting and perfect power supply to the AP Drive/Clutch.
Are there any other possible causes that I could investigate ?

[Derek - Raymarine - Moderator]

Hi umuk,
Thanks for the feedback,

Other issues could be damaged cable or a high resistance joint leading to a drop in voltage as more current is drawn. the best test is to measure the voltages when the drive unit is under load and working hard, this will show up any weaknesses in power supply.

if in doubt, tun two new thick, ( 4mm sq or larger) direct from the batteries to the course computer, if this resolves the isse, then you definitely have some issue with the cabling between the batteries and the pilot.

If no issues at all are identified, then get the autopilot cpomputer and drive back to the nearest Raymarine agent to test and evaluate.
Regards
Derek

[SeaTroller]

I also have this issue.However when pushing "auto" I often get a "start up"on the 6002. I've tried waiting the required 30seconds,Sometimes it goes to "auto',other times back to "start up" I also have checked and rechecked electrical.

[Louise - Raymarine - Moderator]

Dear SeaTroller,

Thank you for your post.

Before we can diagnose this, can you confirm the meaning of 'start up'? Is the control head power cycling?

Many Thanks
Louise

[SeaTroller]

The word "start up" appears on my st6002 screen.

[Louise - Raymarine - Moderator]

Dear SeaTroller,

Thank you for confirming.

If you are continually getting this message, firstly measure the power with a voltmeter to ensure there is a consistent and healthy 12v supply. Are all connections free of corrossion and breaks?

If the power supply is good and the installation is healthy, send the S1G to our service department for testing. This can be done on our website here.

Many Thanks
Louise

[SeaTroller]

Thanks for response.Which of the component do I need to send.I have only the 4 basic ones.

[Louise - Raymarine - Moderator]

Dear SeaTroller,

The S1G is the course computer, it is the grey rectangular unit that the drive unit, fluxgate compass and rudder reference unit connect to.

Many Thanks
Louise