Please help: AP Raymarine S2 Smart Pilot compass heading stucks at 170 degrees

[CaptainRivet]

Hi all,
Please help, need to sail my „new“ FP Lavezzi from Mallorca to Lanzarote to swap my stuff over but the Raymarine AP is not working. Previous owner said only motor of type 1 linear drive is broken and I replaced it with an overhauled type 1 linear drive.
I have the following behavior:
- the St 6001+ Shows 170 degrees and sticks to 170 when the heading is 0 to 170 degrees, above 180 it jumps by 10-30 degrees increments.
- the degrees shown on AP are off by 100 degrees or more and not useable.
- AP cannot be calibrated, shows „turn“ when driving circles even we done 8 times already

Its a FP Lavezzi with Raymarine AP Smart Pilot S2 with Fluxgate, St 60 Multi, St 6001
I have checked the following:
- mounting location of the fluxgate compass is at the water level facing forward and free from magnetic fields
- fluxgate measured on 200ohm with a multimeter showing that following:
Shield against blue 8 ohm, shield against all other OL
Red against green and yellow 5ohm
Yellow against green 8 ohm and red 5Ohm. All other OL

Is the fluxgate ok? What can I measure to figure out what’s wrong?

[Emmalina]

You can't really test a fluxgate with a multimeter ! But it sure sounds like thats your problem.

[stormalong]

Before you spring for a new compass check the wire connections at the course computer. It is unlikely that the cable is bad but inspect it's full length for damage. If it's all good then replace the core of the compass. You do not need to replace the whole compass. Raymariine sells the core and it plugs right in to the housing.

[CaptainRivet]

Originally Posted by Emmalina

You can't really test a fluxgate with a multimeter ! But it sure sounds like thats your problem.

Thanks but Raymarine has a support thread (sorry in German) where they describe how to check the fluxgate with a multimeter:
Überprüfung eines Fluxgate-Kompass M81190 (German)

And from that the fluxgate looks ok but not sure as they say 10 ohm and in brackets 8ohm, mine has 8....
Compass sounds and will be the cheapest solution to fix the problem.

[Mike Banks]

Switch it to satellite mode (links with GPS) and see if it works, If it does, then your flux gate compass is stuck

[Boatwright]

Where are you testing? If at the compass, you haven't eliminated the possibility of a wire or connector defect. Bad connections, in my experience are the problem with electronics at least half the time. If at the controller, disconnect the wires from the compass first and don't use your fingers to hold the probes to the wires -- get some proper clips so you aren't reading the resistance of your skin.

A very common source of bad connections is cheap crimp connectors. It is a false economy to pay a nickle for connectors instead of using quality solid barrel, tinned copper, fastened with a pro crimp tool and sealed with moisture proof heat shrink. Folks are often put off by the outrageous prices charged at chain marine stores, but with a little effort one can find the same items from internet retailers for 1/2 the price. Ditto with automotive hook-up wire vs quality marine grade.

$9.99 digital multimeters -- you get what you pay for. Be sure you are taking resistance readings with the power off to the entire system and with the correct range selected.

I would also be taking a very careful look at the wiring connections to your autopilot controller to make sure you don't have a mistake there -- with the row of terminals in the Raymarine units it is very easy to get one wrong.

[timeout2]

Originally Posted by Emmalina

You can't really test a fluxgate with a multimeter ! But it sure sounds like thats your problem.

Yes you can and his measurements indicate the fluxgate compass is likely within spec.

The S2/ST6001 are many generations old. I would not waste a lot of time or money on them. There are numerous S2G/S3G units for sale on EBay Control heads are a little pricier but if upgrading to S3G or ACU series course computer doesn't work I'd start swapping control heads.

The linear drive is either on or off and you can check it's functionality by connecting leads directly to battery.

[CaptainRivet]

Originally Posted by Mike Banks

Switch it to satellite mode (links with GPS) and see if it works, If it does, then your flux gate compass is stuck

How do I switch it to satellite mode?

[CaptainRivet]

Originally Posted by Boatwright

Where are you testing? If at the compass, you haven't eliminated the possibility of a wire or connector defect. Bad connections, in my experience are the problem with electronics at least half the time. If at the controller, disconnect the wires from the compass first and don't use your fingers to hold the probes to the wires -- get some proper clips so you aren't reading the resistance of your skin.

A very common source of bad connections is cheap crimp connectors. It is a false economy to pay a nickle for connectors instead of using quality solid barrel, tinned copper, fastened with a pro crimp tool and sealed with moisture proof heat shrink. Folks are often put off by the outrageous prices charged at chain marine stores, but with a little effort one can find the same items from internet retailers for 1/2 the price. Ditto with automotive hook-up wire vs quality marine grade.

$9.99 digital multimeters -- you get what you pay for. Be sure you are taking resistance readings with the power off to the entire system and with the correct range selected.

I would also be taking a very careful look at the wiring connections to your autopilot controller to make sure you don't have a mistake there -- with the row of terminals in the Raymarine units it is very easy to get one wrong.

I disconnected the compass completly and measured its bare wire ends with my 300Euro Multimeter and proper clamps.
Looks within spec but if I turn it in my hands and attached to the S2 it shows the behavior above.

Bare wire ends go into push down clamps at the S2 Smart pilot. Checked 3 times to have them connected correctly.

I just put a factory overhauled lineardrive typ 1 in 1 week ago.

[CaptainRivet]

The fluxgate shows a quite similar behavior in this repair thread.

https://m.youtube.com/watch?v=9fVrynrjbB4