When I turn my AP on, it holds course for about 30 seconds and then begins to direct the rudder off course. It continues making numerous changes to the same direction until we are off course by 45 degrees or so and I shut down the AP. It varies which way off course it will go. Sometimes it is to port sometimes to starboard.
I used to have a hydraulic leak which would alway drift the boat to port. This leak has been corrected.
Which unit should I send in for testing? The flux compass or the brain. Thanks. What are the charges for testing?