Raymarine ST6002 Locks up

Jul 11, 2023
3
catalina 30 sandusky
so having this very bizarre issue with my Autopilot that has me perplexed. Sometime I'll set a course, engage the Auto, and no issues, it holds course, you can see the wheel adjusting and everything works fine. then other times I'll set a heading, engage, it displays the heading and it literally does nothing but just lock the wheel and wander off, the minute I disengage it by hitting Standby, it then shows the correct heading the boat is now on. doesn't matter what the conditions are (wind, waves, etc.) it's as if it has no clue that the heading was wrong. it occurs randomly but seems to be getting worse. I checked and cleaned all connections to no avail. is this a symptom of my fluxgate compass going bad? Thanks.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,281
CAL 35 Cruiser #21 moored EVERETT WA
Have checked the wheel of the AP. Sometimes gears, the drive wheel or the nut threads get loose or break. This can cause the drive to seem lost. It’s not it just cannot turn the boat to your course. I would eliminate the wheel from being the cause before I start chasing electronic gremlins.
 
Jul 11, 2023
3
catalina 30 sandusky
I mean when I engage the wheel it locks it up pretty good. and I don't hear the drive trying to do anything to correct the wheel. I don't know, if something was loose I'm guessing I'd at leat hear it trying to work or feel play in the actual helm but it all seems pretty solid.
 
Jan 7, 2011
5,663
Oday 322 East Chicago, IN
I assume you have a wheel pilot mounted on the wheel.

The drive motor mounted to the wheel ring has a pretty weak wire loom on top of the motor. The 2 wires carry power to the drive motor. If these wires are loose or broken, it could cause intermittent issues. I broke mine on my old ST4000 and had to rebuilt the
wire loom.

The other thing to check is the drive motor wire connections on the brain box. Ideally, put a multi-meter on the drive connections, engage the AP and then tell it to tack or turn 20 degrees and see if you are seeing any power on the DVM.

I installed an ST6002 and a new rudder sensor. Due to the location, I mounted the rudder sensor upside down. I missed the note that said to reverse the sensor wires if you mount it upside down. I went out for a sea trial, and things started out good, but as soon as the AP tried to correct course, the dang thing did a Crazy Ivan. I scratched my head for a while until I realized that the rudder sensor was showing “backwards” on my display. I reversed the wires while still on the water, and everything worked great after that.
 
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