ST4000 autopilot problem

[Bob K]

Autopilot stopped working one day this past summer   When in auto, the compass reading never changed, and the motor never actuated.  It read "A034".  When in standby mode the reading never changed either, it read "C034", with the C flashing.

I verified the motor worked by pressing the +10 and -10 keys. 

I also tried the compass deviation correction routine (slow 360 degree circle), but it never displayed the deviation, as I sort of  expected.

My first thought was the fluxgate compass died, but I did a functional (resistance) test as described in the ST4000 service manual, and all connector pin resistances were in spec. 

So I removed the control head this week with the intent of sending it to Raymarine for checkout.  I just found out they no longer service the head, so I am stuck trying to figure this out for myself.   I can gamble and try to find a used head somewhere, but I am unsure if the problem really is the control head or maybe is the compass. 

Has anyone ever experienced this type failure, or can offer some troubleshoot advice?

Th

[Bobg]

probably won't help, but I had a lot of trouble with mine also, until I took the cover off and drained all the water that accumulated there.  even after that I would get a 90 degree turn occasionally, never trust these units

[Ken Juul]

Internal water also fried mine.  Is the C034 an error code or the course the controller is trying to maintain?

[Bob K]

Ken I don't think it was an error code as there is no reference to error codes in the service manual. Looked like a stuck heading.  May need to bite the bullet and get a replacement head and hope that resolves it.

[tonywright]

The problem is that Raymarine does not sell replacements for it. They have reeingineered the unit and split the computational unit out from the display head in the new X series. The wheel unit is compatible, but the head is not.

Tony

[Ken Juul]

I have not done the flux compass test, does it involve rotating the compass to see if the values change?  If no maybe it is the fluxgate.  I have a spare if it turns out bad.

If you are sure the Fluxgate is ok, then it is not communicating with the control head. I think I would open the control head.  It probably has water in it.  Dry it out well and look/smell for any burnt out components.  Also look for corroded connections inside that may be the cause.  I'll have to look to see if I still have my old control head laying around.

In the old days, RM used to let local shops do repairs.  If you can find an "authorized RM" shop that has been around 8-10 years, perhaps they still have the repair manuals/drawing.  Although they are not supposed to repair anymore, since it is out of warrenty and it is probably a real slow season for them, maybe they will take a shot at repairing.

[Bob K]

Ken ,
I did look inside my control head, and the insides look pristine, so I don't think water ever got into it.  Regarding the fluxgate tests, I performed only a pin resistance test, as that is the only test outlined in the service manual.  When the problem first surfaced, I saw no change in the compass heading display as I turned the boat.  So I am really not sure if it is the compass or the fluxgate.  I do have the service manual with schematic diagram, and have an oscilloscope, so next step may be to hook it all back up and monitor the signal lines from the compass.  Not sure if that will lead to anything but worth a shot if I get a warm weekend day.  Easier to swap components - I am interested in buying your fluxgate and head if you want to part with them!!

[Ken Juul]

I'll check at home tonight to make sure I still have them and let you know.