Autohelm ST7000

[S/V Elusive]

Sounds like a fluxgate compass - make sure all connections are still good. with the autopilot on, and fluxgate un-mounted, turn the compass one way then the other. Your pilot should respond. If not, you know where the problem most likely is (still could be the interface in the main computer).

Good Luck.

[Pblais]

Perhaps you too can have something simple. Assuming it ever worked right could you have loaded something metal near the fluxgate in a locker or cabinet. It is a common thing. I would see if something has changed / moved on the boat. It could be that simple. I know a great repair guy that can fix all this stuff and this problem happens a great deal.

You can test it if you remove the compass and relocate it. The signal problem may be from a loose or chaffed wire. Loose wire connection could also be a problem. After that I would see about the compass. You can disconnect it from it's mount and leave it wired up. You should be able to rotate the compass in your hand in the slip to simulate operation. This can be a lot easier than driving in circles since the boat is not moving. Try going in 45 degree increments in both directions and validate the heading change. Have a helper read off the numbers. Repeat this several times in the slip. Then you can see if you can find the loose wire or if the compass has gone belly up.

If you disconnect it and it won't fail then the metal objects start to sound like the plausible idea.

[yachtsman44]

responding to the 2 suggestions....the compass is indeed an Autohelm fluxgate compass in the same location it has been for many years.
1. during yesterday's episode no objects near the compass were moved or changed, yet after 2 hours it simply started working.

2. during yesterday's episode sea conditions were absolutely flat, so without extensive motion, there is little reason to suppose that a loose connection would have changed to start the autopilot working again. I have inspected the compass visually and nothing seems loose, or unusual and the wires from it going up to the control unit appear to be original with no splices, so a bad connection seems very unlikely.

Are there any moving parts in the fluxgate compass?
What would cause a solid state device to have intermittent outages?

[Pblais]

Are there any moving parts in the fluxgate compass?

Yes and no<g>. The compass part looks like a small donut with a coil wrapped around it. Inside there is stuff that moves inside but it's sealed. I would still see if you can operate the compass manually and make the readings change. You may find a dead spot. The whole process works on quadrants so when you see errors in quadrants of 90 degrees the compass or it's location is a good bet. The rest of the controls are solid state but they could go bad from heat or other problems. Anything is possible but without a bench test the compass is all you can play with without uninstalling it.

From my rounds with an expert last season on the other boat it's the compass this guy started and ended with. He at one point thought it was the main board but what neither of us knew is the thing never really worked accurately ever in it's life because of an install problem. It only worked for me when it was flat water and didn't need to correct anything. The PO lied when he said all it needed was the sea trial calibration because it never could pass. Once the location was changed it was a perfect device. I was upset we were selling the boat.

We have an ST7000 on or boat now and it can hold course in 4 ft of chop with 30 knot winds under sail or power. The ST7000 is plenty powerful. The only time I didn't find it worked perfect was in stronger winds (40) with higher chop (8ft). The stern falling off the waves was not something it was quick enough at. I could do it by hand but only because I could anticipate the coming action where the auto helm logic really could not. Simrad logic I think is better. It's all magic. The thing learns the sea state on it's own and finds the right amount of rudder where the Autohelm you have to set it 1, 2, or 3 for the reaction cycle time.

[yachtsman44]

Update on symptoms.

We have been sitting at a dock for 2 days now. The magnetic compass says we are pointing nominally at 080.

Yesterday afternoon when I turned on the elctronics the ST7000 displayed 083.....seemed ok, but I remembered seeing 113 the previous day, but dismissed it as faulty memory.

This morning I turned on the electronics and the ST7000 is displaying 113.......

NOTHING HAS CHANGED....no equipment is near the fluxgate sensor and nothing has been moved. Seems like there is a 30 degree error ocurring and I don't know that "swinging" the sensor manually will prove anything, but I will take out the screws and try it so see.

Is the "brain" the display unit itself or should I be looking for another black box somewhere?

[Pblais]

NOTHING HAS CHANGED....no equipment is near the fluxgate sensor and nothing has been moved. Seems like there is a 30 degree error ocurring and I don't know that "swinging" the sensor manually will prove anything, but I will take out the screws and try it so see.

I've been there too!

In my case is was the location of the compass. There was nothing near that should have casued the problem yet there was. If you have enough wire to move it some place that you can make stable I would then try to recalibrate it and see.

[yachtsman44]

Tried the suggested relocation yesterday.

Moved the compass farther away from everything after opening and inspecting it to make sure there is no obvious loose connection inside or any corrosion, etc. Looks fine, no moving parts except the gimbals that move freely. Secured the fluxgate to a vertical and watched the display settle on 080 which is identical to the magnetic heading of the boat in the slip.

This morning, turned on the autopilot and it was still showing 080, but now an hour later, with nothing having changed.....it displays 113. I think it may still track, but am at a loss to explain why this changing heading display. Yesterday, before the relocation, I happened to be looking at the display as it changed before my eyes in one swoop from 085 to 113.

Raymarine, has told me that the problem could be a bad fluxgate or a loose connection, or a bad computer. They say the only way to confirm the fluxgate is to get a replacement, which is available. The computer and the ST7000 display, they claim is no longer being worked on.

Any other ideas are welcome.

[Pblais]

Try removing the compass and manually rotate it horizontally in a clockwise then a counter clockwise through 2 double circle. Pause at each 45 degree increment and have someone read the display. Using this method you can determine a potential problem in the compass. The fluxgate needs to compute the quadrants properly and it alone does that computation. If it fails this test the compass is bad or the location is bad. Wires could be bad too but it may get you some information that can lead to the answer.

If you can read the values and not have them screw up it generally means the location is bad and who knows why. When I went through this we never found the reason but found a location that was perfect. I would not assume the location is good you really need to pretend like was a totally new installation. If you could make a new set of wires so you could reconnect it to the system and then be able to try other locations that too could rule out the wires.

The ugly party of all this if you start replacing parts you can't send them back for a refund if they are not bad. Main boards are not cheap but they can be worked on even if Raymarine won't. I know a guy<g>. Fluxgates may not be that bad but are easier to install. The wires and playing with the compass you can all do for free. You are at a point where nothing can be assumed to be good. You really need to get very systematic about tracking this down.

You may want to review the on the water and dockside calibration procedures. Recalibration can be a something that may help. The calibration attempts to build a stored table of corrections to be applied to the 360 degrees of the compass. It is set up so the magnetic variations caused by the boat can be computed so that the computer can create a nice smooth circle from the fluxgate readings. If a table value went haywire it could show up as some points of the compass being goofy. This is where the manual test above might lead you to find what the symptoms of your disease really is and may help you try some things that would make a repair of one part likely to be a success. If the table is bad then it could be rebuilt through calibration and if not then it may be a compass issue or a computer issue. The details of how it screws up may point you in the better direction.

Good luck.

Troubleshooting this stuff can consume a lot of time. You could expect to pay for 8 to 10 hours labor to install a new system by someone that really does them often and well. Add the cost of the new system and of course it's now larger numbers. All the steps I mentioned were all done on my boat by someone that really knows this stuff. It took about 6 hours worth of his time to find the problem on my own I never would have found it. You sometimes can't believe what is happening is possible until you get the whole answer and then you just slap the forehead and wonder how you missed it.

[mikemr]

Hello, I have been following this thread in hope that I can find a clue as to why our auto pilot randomly goes off but will come back on after being shut down for a short while. It displays a rudder drive error message. We will be at the Severn River Marina soon and I was wondering if the person you had do work on your boat was available, if so please let me know what would be the best way to get in touch, thanks, mike.

[Pblais]

Mike send me a private email.

[scotte]

Have you tried doing a recalibration of the compass, using the setup mode where you slowly make circles? There's a few other config options that can affect it to, like your present latitude. Note I've got a 7000+, and I'm not sure where it varies from the 7000, though all this has to do with A/P computer, not the head unit as far as I know.

[isail43]

my st7000 shows No Link and switches to ST700 beeping every half-minute. what should i check?