[DG] [DG11] ST2000 sudden hard course changes

[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