[DG] [DG11] ST7001 Autopilot Not Displaying HDG or COG

[mikeyor]

I have the following Raymarine equipment installed on my Catalina 470 sailboat:

eS98 (master), eS128, ST7001 autopilot with type 100/300 course computer, heading sensor and fluxgate compass, ST60 wind, speed and depth. The ST and autopilot equipment was factory installed during the boat build in 2002

Everything was working normally until two weeks ago.

When I switch on the autopilot the ST7001 is no longer displaying the heading in Standby or a COG if I switch it to Auto. All that displays on the ST7001 are the words “standby” or “ automatic”. The rest of the display is blank except for the rudder reference bars which move normally as the wheel is turned.

On my mooring, with the boat moving around, the MFD shows a heading of 050 degrees no matter what the real heading is as the boat swings around. If I select Autopilot 050 degrees shows up as the locked heading. The boat’s icon on the MFD points to about 050 degrees regardless of the actual heading. If I move the boat along a straight line course the boat’s icon still shows an incorrect orientation but the COG arrow extends from the icon in the correct direction.

I have disconnected, cleaned and reconnected the SeaTalk connections. No change in status. I have not yet recalibrated the autopilot.

I would be most grateful if you could suggest any diagnostics that would help me zero in on the problem. I am guessing, possibly incorrectly, that either the fluxgate compass or the heading sensor may be at fault.

I look forward to seeing your always excellent advice.

Many Thanks

Michael Yorke