Autohelm ST 7000 all of sudden wont hold course...

[tstano]

Mine went last summer and will be getting a Raymarine Sailpilot EV-400 to replace it. The computer internals were fried, but it was easy to check. 12V coming and nothing going out to the control arm on the rudder. Had the local tech verify and then he took the computer to bench test it. While undoing the wires from the fluxgate and rudder sensor we had to cut them because the ends were soldered tight to the computer. Hopefully yours won't be like mine. I have a service manual but I'm not sure how to post it. Got it from a sailor in Bristol, RI. PM me and I'll give it a try.

[TheThunderbird]

With no offence, do you use 15yo electronics at home?!

:-)

[ka4wja]

j,
One important thing I had in last night's posting (that didn't post), was a question about what the alarm was???

Was this an off course alarm, Drive Stop alarm, SeaTalk alarm, etc. etc.???
(BTW, a "drive stop" alarm, points to rudder position sensor issue...or a drive issue...)

Knowing the answer to just those questions, will point us pretty directly to the problem!!


I really wish my post from yesterday had posted, 'cause it had a lot of good info in it...


Please advise / add more details, and we'll try to help more...


John

[CarinaPDX]

Lots of good advice here. Some comments:

There could be resistance anywhere in the power supply, which wouldn't cause enough drop in voltage to be a problem until the drive unit was powered (causing a drop in voltage and disabling the computer). Check the voltage level when operating.

The old flux gate compass is very simple, and easy to troubleshoot. Use Raymarine's procedure. But simplistically just open the case and check the resistance back to the computer for each wire. There are no active electronics inside the compass, so short of corrosion there will likely not be a problem inside. However the sensing of the flux gate is done in the computer - the wires are carrying an analog signal so they are very sensitive to damage/interference. Also, as others have noted, the compass is sensitive to steel anywhere nearby.

If you have a version of computer that can take an NMEA (0183 or 2000) compass input then buy one of them if you are going to replace the old flux gate - it is an antique and not the best performing.

It is devilishly hard to troubleshoot from afar with the information given. You are better off finding someone who is capable of checking it out in person. It could be a Raymarine rep, but you should find a cruiser who understands these things. There are a lot of them floating around the Caribbean.

Good luck,

Greg

[Jbingham]

Originally Posted by phantomracer

had a similar problem with my st7000. was a bad connection with the fluxgate.

the reading on the head unit reading accurate?

the actuator working correctly?

Could be a bad rudder sensor as well.

wind/speed working? mine worked better when the speedo was working.

we have a KVH heading sensor on our boat. works quite well

Yep everything else working as it should be. Are the flux gate compass and rudder sensor parts that are still available?


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[Jbingham]

Originally Posted by phantomracer

unsure of the autohelm heading sensor (or other heading sensor),but the KVH is always in autocompensation mode. Only have to do slow circles once to calibrate it.



It has to be either the heading sensor, or rudder sensor. Its really the only 2 inputs (other than, perhaps, wind/speed)



If the heading on the display is accurate, I would tend to lean toward a rudder sensor.

I would definitely be interested in compass. Message me details. It's worth flying down with just in case. Parts in virgin gorda don't come easily!


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[Jbingham]

Originally Posted by ka4wja

j,
I thought I replied to this thread yesterday, but somehow it didn't post....oh well, here's the gist of what I wrote...


I'm assuming (along with the others here) that you have an older Autohelm / Raymarine belowdeck autopilot of either a type/model 100/150, 300/400 (or the newer S1, S2, S3 series, either with rate gyro or without), and the control head / display in your install is the ST-7000???
(all below is assuming that is correct..)

I understand the complications/frustrations associated with troubleshooting this problem from 1000's of miles away...it's what we do here all the time!

It initially sounds like a heading sensor / fluxgate issue, or a rudder position sensor issue....but without further detail, we are all guessing!
And, while I agree that "swinging" the compass is a good idea....you may want to look for a simpler cause to the problem first...


1) Look at the ST-7000 control head / display (or have someone you trust do it now, while you are on the phone with them, before you order any parts!!), with the autopilot On and in Standby....
Have then turn the wheel and make note of the rudder position indicated on the display....
If it is showing accurately and follows the actual rudder angle smoothly....then it is working at that specific moment....but we cannot be sure that it is always working...

Also, have them note the heading displayed....it should be very close to your main steering compass, of course!!
If the boat is on a mooring / at anchor, you're lucky...as you can have them just turn the boat in semi-circle, while watching the steering compass vs. the autopilot heading...
If there are wide variations, then you've found the proximate cause of your problem....(whether it is faulty, the wiring/connections are bad, or you have something metallic where it shouldn't be....still needs to be determined!)


2) Next is to have them look for metallic objects near the heading sensor / fluxgate compass...
Have them look for any new metallic objects (or electrical wiring / electronics) within a few feet of your heading sensor/fluxgate compass...
{True story: One of my brothers found a car of shaving cream on the floor of the aft head, and instead of putting in one of the head lockers, he stuffed it in UNDER one of the aft cabin lockers (never sure why!), and that placed it about 12" away from my heading sensor....and that metal can of shaving cream changed my heading by 20* - 40* depending on exact heading...
When I went looking for the problem, the first thing I went to was the heading sensor to look at its wiring / mounting....and as I was about to dismount it and "swing" it by hand, I saw that damn can of shaving cream, pulled the can out and threw it across the cabin....and all was now well with the world!!!}


3) If those simple tests/examinations show no issues, then have a look at the wiring / connections of all the autopilot wiring, specifically the heading sensor and rudder position sensor wiring....




4) If all of those show no issues, then proceed to swing the compass....
If you do not have anyone there that can perform this (which is a LOT to assume that any dockmaster would even attempt, let alone complete successfully), then I'd say buy a new heading sensor and wiring, and take that with you when you fly down to the boat...

The Raymarine heading sensors of today should work fine for you (but not sure what autopilot you actually have, so cannot be 100% certain), and they are only a few hundred dollars....and will fit in your pocket!




5) Should you have another problem, which you'd need someone on-board to test/troubleshoot for, then you may in fact need other replacement parts....

In order of probable failure, some other parts that have failures:
-- autopilot wiring / connections (cheap)
-- rudder position sensor $
-- autopilot itself (corepak) $$$$
-- drive clutch $
-- drive $$$
-- control head $$


Not sure if I helped much....but 'til you provide more details, and/or get someone on-board to do some hands-on troubleshooting, that's about all I have...

Fair winds...

John

This is awesome feedback. I'm sending this down to someone for sure. I'll have them test early this week!!!


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[Jbingham]

Originally Posted by TheThunderbird

With no offence, do you use 15yo electronics at home?!



:-)

Ummmm. Do you own a boat haha?? Yeah I'll just replace everything and send the 50k bill to what's your address?? 😜


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[phantomracer]

Originally Posted by Jbingham

Yep everything else working as it should be. Are the flux gate compass and rudder sensor parts that are still available?

Unsure about new, but I am sure rudder sensors pop up on ebay time to time.

Unless your NMEA IN port is being used. you can use pretty much any heading sensor (fluxgate).

Unsure what alarm is going off.. If it is off course, I would lean toward something other than the heading sensor..I never got an off course alarm when I had the wiring problem with the fluxgate.

if the AP cant hold a course due to strong wind/current/tide/poor sail trim, the AP will sound an off course alarm if it can't stay on course. be similar as a rudder sensor giving the wrong feedback to the computer. Or the computer could be having serious gas pains.

If you are getting correct readings on your AP display, I would be less likely to blame the fluxgate.

If you were going off course, with no alarm, I would bet the fluxgate , but the (I assume) off course alarm, to me, would indicate something other than the fluxgate.

Also, Raymarine has been quite good about troubleshooting the old autohelm stuff.

[ka4wja]

j,
I'm glad to be of help...
But, be sure to verify what autopilot you have on-board,
BEFORE anyone does anything!

Originally Posted by Jbingham

This is awesome feedback. I'm sending this down to someone for sure. I'll have them test early this week!!!

Fair winds...

John

[Jbingham]

here's the update from Cay Electronics out of Tortola...

Hi Jonathon,

The techs had a look at Robin Hood on Friday. They identified two problems. One there is some air in the hydraulics and the fluid is dirty - the system needs to be drained and flushed out then refilled and bled. The second problem is the course computer which is not sending proper drive commands to the pump. The system you have is very old. The course computer (T300) is obsolete and has not been repairable for some time. I recommend upgrading to a new Raymarine EV400 Sail autopilot. The price of this is US$2894 and includes the EV-1 sensor core, ACU-400, P70 control head and Evolution cable kit. Some additional STng cables may be required. The system would use the existing drive unit.

[phantomracer]

There are used computers out there that might be a good alternative...however more risky. but far less spendy, if you happen to get a good one

unsure if you can use it, found 2 type 100 computers on ebay for 300

[CarinaPDX]

If you are repairing the hydraulic drive system and replacing the electronics then you can choose from any of the available AP controllers, not just Raymarine - there is nothing proprietary about your drive interface. My impression is that RM fell behind a while back but their current offerings are competitive; still, there are other excellent computers to consider. You might do a little research into alternatives.

Greg

[Jbingham]

Originally Posted by CarinaPDX

If you are repairing the hydraulic drive system and replacing the electronics then you can choose from any of the available AP controllers, not just Raymarine - there is nothing proprietary about your drive interface. My impression is that RM fell behind a while back but their current offerings are competitive; still, there are other excellent computers to consider. You might do a little research into alternatives.

Greg

We did a ton of research this past fall before installing AIS (raymarine). Depends who you talk to was the consensus for us. Garmin, simrad, B&G, raymarine. They are all good. We stuck with raymarine because we are replacing one system at a time and couldn't do the whole lot at once... We are keeping the drive unit itself which (for now) is fine.


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[Jbingham]

Originally Posted by phantomracer

There are used computers out there that might be a good alternative...however more risky. but far less spendy, if you happen to get a good one

unsure if you can use it, found 2 type 100 computers on ebay for 300

If I was troubleshooting this at our dock in Boston I hear you. But I got hit with a 600.00 bill just to get this diagnosed. Being on a remote island in the bvis complicates this quickly and I'm learning if you could use an upgrade bite the bullet and make it fast or you'll have a monster service bill in a New York minute. Sucks but that's the reality when you're 1600 miles away...


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