Raymarine forum

My SPX30 autopilot loses the correct heading whenever I power down the system. When I first start using my boat, I align the heading using the setup procedure with the GPS. The heading will usually be correct until I turn the boat around 180 degrees or shut down the instruments. The SPX30 is connected to a E120W which otherwise works correct, including the magnetic heading from the fluxgate compass and the green vector line.
Also the ST 70 autopilot display works correct, and I can control the autopilot from the ST 70, the E120 or the Smartpilot remote. I do not think there is a problem with the GPS receiver as the E120 always seems to show the boats correct position, but sometimes the boat icon and red vector line is not showing the correct direction to the boats actual heading.

Welcome to the Raymarine Forum Andrew,

It is recommended that the autopilot's fluxgate compass be tested. Please click here to view a FAQ addressing how to do so. Should no fault be found with the autopilot's fluxgate compass, then it would appear that the autopilot course computer has suffered a failure and should be sent to Raymarine’s Product Repair Center to be bench checked / serviced.

I have checked out the fluxgate as per instructions, and it all checks correct. Question, does the fluxgate create the heading information or is this generated from the GPS?

Andrew,

The fluxgate compass in combination with the autopilot course computer determine the sensed heading value. In short analog signals from the fluxgate compass are used by the autopilot course computer to determine heading.