[CA] [CA11] ST5000+ Control Head malfunction verification

[avalonS211]

I have a ST5000+ auto pilot with Mechanical Type 1 Drive on a 36ft sailboat.

the boat is new to me, I believe the autopilot was fitted at some point in the late 90's maybe? (Not sure the release date of the ST5000+)

Anyway....It is not functioning properly. I have spent quite a bit of time reading here and going through the troubleshooting steps listed in other posts, FAQs and documents.

Here is what I have found:

1. The FluxGate compass is okay. The testing with multimeter showed the proper readings.
2. The FLuxGate compass does need to be relocated as a AC unit was installed recently and is under the sink where the compass is.
3. The failure modes on the autopilot are: the dockside rudder calibration fails. The procedure starts with short stuttering moves to starboard then it goes to lock and reverses, once on port lock it just keeps trying, it does not return to center, and I hit STANDBY and cancel the calibration.
4. Sea Trial compass calibration works and finds 33 degrees deviation. which is high and expected due to the AC unit too close.
5. Hitting AUTO underway the autopilot goes full when it makes the first course adjustment.
6. Rudder sensor functions.

Questions:

1. Is the control head at fault?
2. Is it worth it to relocate the compass and try again or is the failure mode more and indication of a failed control head?
3. Is there anything else I can look for? Drive connectors?
4. How does the unit know when rudder has reached full lock? Is it in the control head or is there a sensor in the drive unit?
5. How do I verify the drive unit is sound for continued use?

I am resided to the fact I will be replacing all of the system or parts.
Option 1 is to replace with the EV-100 Sail wheel pilot. More affordable.
Option 2 is to verify Type 1 drive is good for more years of use and go to the EV200 system pack (more expensive but retains the Type 1 drive, rudder sensor)

Help much appreciated...

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum,

Q1. Is the control head at fault?
A1. First, understand that the ST4000/ST4000+/ST5000/ST5000+ combine autopilot course computer and control head within a single device. I'm not convinced that the ST5000+ has suffered a failure. It is recommended that the fluxgate compass be relocated to permit the compass to be re-calibrated and aligned. After doing so, it is recommended that the vessel be turned very slowly clockwise and counterclockwise through 360 degrees to determine whether there is any binding in the compass (i.e. pauses in heading changes). It is additionally recommended that the rudder reference transducer be tested. Testing should additionally include slowly turning the rudder fully to port and starboard to ensure that there are no pauses or loss of rudder data. Finally, the autopilot's rudder limit configuration setting should be configured to a value which is 5 degrees less than the maximum rudder angle reported.

Q2. Is it worth it to relocate the compass and try again or is the failure mode more and indication of a failed control head?
A2. Yes. See the response to Q1.

Q3. Is there anything else I can look for? Drive connectors?
A3. See the response to Q1.

Q4. How does the unit know when rudder has reached full lock? Is it in the control head or is there a sensor in the drive unit?
A4. Rudder limit is configured via the control head.

Q5. How do I verify the drive unit is sound for continued use?
A5. Essentially, if the drive unit is able to shift the rudder to port and starboard without binding, then the drive unit would be considered to be operational.

Q6. I am resided to the fact I will be replacing all of the system or parts.
Option 1 is to replace with the EV-100 Sail wheel pilot. More affordable.
Option 2 is to verify Type 1 drive is good for more years of use and go to the EV200 system pack (more expensive but retains the Type 1 drive, rudder sensor)
A6. Such choices are subjective. I'm partial to below decks drive units and would certainly recommend one over a wheel drive it. I haven't seen anything in your problem description to lead me to believe that there is anything wrong with your drive unit. The Evolution EV-200 Sail includes a rudder reference transducer.

[avalonS211]

Thanks very much for the response....I will relocate the compass and go through the setup and calibration procedures again...I just have to find a place to put the compass. I'll review the docs on the compass sensor again.

I drop a note back here in with the results...

[Chuck - Raymarine - Moderator]

You're welcome.

[avalonS211]

Update

I relocated the compass to a spot with little magnetic fields. To move the compass I had to cut the cable and splice. Pulling the cable with messenger line from the pedestal forward was not possible without pulling all the cables in the pedestal out and redoing the entire run, something I'll leave for the next instrument upgrade as the current combo are working at this time.

I made the adjustment to the Rudder Limit and went through the dockside procedures and test. The rudder calibration worked though it was backwards. I swapped the drive leads per manual and calibrated the rudder and it worked properly.

Dockside test hitting auto and +10 showed expected behavior as described in the manual.

Measuring the magnetic field where the compass was it was no wonder it was malfunctioning. Just inches from the compass is the intake pump for the AC system. Previous owner had installed the AC and said the autopilot didn't work after that.

I used a small terminal block for the splice. I cut the compass cable a few feet from the unit and ran the pedestal line through cable routes under the floor to a a bulkhead separating the nav-station from the salon. Location is is just outside of three feet from any magnetic source.

This past weekend I was able to do initial sea trial compass calibration and heading adjustment. The compass calibrated with a 5 degree deviation and I was able to run through most functions with success.

Yay!

[Chuck - Raymarine - Moderator]

Congrats and thanks for the follow-up.