[DG] [DG11] ST2000 sudden hard course changes

[Robert_Aue]

Hello!

we are using an ST2000 tiller pilot on our boat. It is an older unit and still has the name 'Autohelm' printed on it. During the summer, it happened a few times that the autopilot would very suddenly give hard rudder (to starboard). The pushrod was pushed out to the maximum extent, while the motor was still working against the stop. The conditions were very calm with perhaps 12 knots of wind and reaching. I immediately disconnected the power supply and re-started the device. Afterwards, it worked just fine but this behaviour can obviously be quite dangerous in some circumstances. Has anyone experienced a similar issue and knows if it can be fixed (and how)?

Kind Regards
Robert

[Derek - Raymarine - Moderator]

Hi Robert,
Thank you for your enquiry.

The description of the unit suggests it is well over 20 years old now so I guess has done some good service for you!

it is possible the unit has been overheating, for example if the movements to a fro are very repetitive, the frequent motor reversals can lead to both the motor getting hot and the drive transistors getting hot - in this case it is possible the heat led to the unit processor malfunctioning, resetting the unit by power cycling reset the processor and normal operation resumed.

In this case, check the deviation measured by the compass - these units could go through a compass linearisation process and this would help the compass smooth out any local deviation, also if you notice the unit constantly hunting this also suggests an issue with local deviation.
For more information please click here which explains deviation further.

it is also possible the compass sensor itself is defective and the unit can be returned to our service workshops or to you local Raymarine agent for further diagnosis.

Also check the general area around the autopilot for sources of local deviation too

regards

Derek

[Robert_Aue]

Dear Derek

Thank you for your reply, I will then find a local dealer.

Best
Robert

[Derek - Raymarine - Moderator]

Hi Robert,
You're welcome
Thanks
Derek