[C320-list] Issues with ST4000+ Autopilot

[Troy Dunn]

I recently installed an RPS on the newer wheel pilot which doesn’t require
one but boy what a difference it makes.   Anyone who has the newer pilot
but doesn’t have the RPS, I can confirm, you probably want one.   It
doesn’t cure all the issues that come along with cheaping out and not
buying a linear drive but…it definitely helps a lot.   Anyhow I digress.
When I was researching some of the 'odd' and ‘searching' behavior of the
autopilot without the RPS, I did stumble across several troubleshooting and
potential issues that can arise with even the older model RPS and fluxgate
compass.   I don’t recall the exact test  procedures (but you can
definitely google and or search on the Raymarine forum) but the interesting
piece of information is that both devices can develop dead spots that can
cause a bad reading.   On the fluxgate compass a dead spot in one of the
windings could cause the compass to report a static heading.   So the test
for this one is kinda simple I think.   Just get your chartplotter to show
a heading line ( not course ) then execute a turn with the autopilot NOT
engaged.   If the heading doesn’t change…you have a broken fluxgate.

For the RPS I think it is less likely a problem because as the autopilot is
going hard over I can’t think of how a dead spot would continue to be a
problem, the RPS would move to a good spot and report an accurate position
back to the computer and pilot head.   It’s worth exploring however.
Again, look at your reported angle as you slowly turn the wheel through all
positions.   If the position suddenly jumps around…problem.

Lastly there can be issues with drive  motor polarity and loose connections
 this seems like it could be an issue and I haven’t got a clue how to start
trouble shooting that other than to try cleaning the contacts to the motor
and maybe looking for obvious signs of wiring or the motor itself going
bad?   Google might be your best friend here.

Anyhow, some of this seems like possible things to check out.

Good Luck!

Troy Dunn
Hull #514