Autohelm going round in circles

[sheppard]

This has defeated the 'experts' so the forum is the obvious choice...

My tiller autohelm (4000+) extends in short bursts of a second or so to its outer limit, then blows its fuse, whenever put into 'Auto'.

In 'Standby' its sense is correct and it works fine, the + and - buttons resulting in correct extension or retraction of the motor arm.

The compass read out on the Autohelm unit reads correctly.

My local experts said they could replace it all for the new model for about £1,000. I believe they probably could.

Raymarine say there is no fault on the control unit. They suggest the motor unit may be faulty, but it responds correctly in 'Standby'. Someone said the compass might be faulty, but it reads accuractely. All the wiring connections look pretty clean and secure - at least there are no corroded lumps anywhere I can see.

There are other Seatalk instruments in the system, but when the Seatalk plugs are removed from the Autohelm, nothing changes (except the other bits turn off of course).

Has anyone had a similar problem and found a fix?

 

[Paulka]

Yessss.
My now "old" 2000 had the very same symptom a few days before the end of the garanty period.
The Autohelm (or Raymarine, or ....) dealer from whom I had bought it made no fuss, and repaired it at no cost.
It still works since then.

I have no idea what was wrong though.

Sorry, this will probably be of no big help,

Paul

 

[FWB]

There are 3 parts, The Tiller arm...Control Unit...Fluxgate Compass.

Have you tried your tiller arm on another boat? or another arm on your boat? This would then leave the other 2 parts as suspect. In that case it would be easy enough to swap the control head to check that.

Do you also have a rudder ref unit? The 4th part not often fitted .... but really worth doing. This could be checked by unplugging it from the control head. Sorry if this is obvious.

 

[jerryat]

My guess is that the fluxgate compass has jammed in position. Had this happen a few years ago on a 2000. These situations produced an identical reaction to that which you are experiencing.

Granted your base unit is fixed (unlike the 2000's which can be laid upside down when storing etc) but is it possible that it has been knocked hard at some time?

It's gimballed so is simple to 'release' again so the gimballs work properly, eithe by a sharpish 'tap' on the casing, or opening it up and manually moving it into position.

Just a thought.

 

[moodycruiser]

The blowing of the fuse is an interesting factor here, as it should be quite normal for an autopilot to go "hard over", without blowing, until such time as approaching desired course when the helm will start to return to midships.

 

[Guest]

From your description it sound like you have no rudder reference connected. The behaviour you are describing is what happens when it cannot correct the course change.

It keeps trying more and more until it hits the end. If it had a rudder reference it would not hit the end.

First, since those units are all common, is the machine coming up in the correct mode? Are the initial words correct. There is a hidden set of button pressed that turn it into any of the other configurations.

I would try reversing the motor connections and see what happens.

This is assuming you are not tied to the dock, you are travelling forward and the rudder actually moves. Anything else and you will see this behaviour. A slight error will move the rudder then unless the boats turns it will just keep trying harder and harder.

 

[FWB]

Have you got a separate power supply to the autopilot? With my set up if I switch the instruments on but forget to switch on the autopilots own supply, the pilot works ok until it has to work hard in which case it trips the instruments breaker.

 

[jollyjacktar]

If the fuse keeps blowing, then the circuit is overloaded, ergo, there is a short or something wrong in the circuit internally and this is manifest in the thing steering in circles. That is it is not working properly. But can it be fixed??!! If Raymarine says it is not at fault then take the unit to them hit them over the head and ask them if it is still faulty. I presume that as they are quite clearly unable to recognize that the unit has a fault then repairing it would be well beyond their capabilities. They would need at least a couple of brain cells to get it working again. Or is this just poor quality staffing. Persisit with the repair option. Good luck. /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif

 

[Richard10002]

[ QUOTE ]
My tiller autohelm (4000+) extends in short bursts of a second or so to its outer limit, then blows its fuse, whenever put into 'Auto'.



[/ QUOTE ]

Does it turn just one way, or does it happen both to Port and to Starboard? If it happens both ways, it sounds like a polarity issue e.g. it wants to alter to starboard, but the reversed polarity means the rudder is moved to turn it to port, so it keeps trying till it blows the fuse.... having said that, mine reverts to standby with an alarm if it cant do what it wants to do.

Has it started happening out of the blue... ie. working fine one day, you dont touch/change any of the wires or system, doesnt work the next day.... or did you change something, then it didnt work.

Is it calibrated so it stops the rudder before the end stops?

Can you power the arm with a 12v supply independently of the control unit?

Not sure if any of this will help, but the answers may help to localise the problem for some of the experts here, and there are 2 or 3 who have been involved in building/designing/servicing these things.

 

[charles_reed]

Problem sounds to be in control head or fluxgate compass.

If Raymarine have tested the former and passed it OK - it's probably in the compass.
Suggest you check if any magnetic material, of any kins, is within 1000mm of the compass.

I had a very similar experience when an aluminium (non-magnetic) beer can was stored, upside down, in the table locker above the fluxgate compass. Though the can and lid was all aluminium, the ring-pull was mild steel. Right side up, the ring-pull was >100mm from the compass and the problem ended.

 

[pvb]

Have you tried...

Have you tried going into the "Dealer set-up" mode and checking that the settings are OK? If unsure, use the default settings.

 

[sheppard]

Re: Have you tried...

Many thanks to all for the suggestions. Will get started on testing all those things. First the compass. It does give sensible read-out on the screen though, so I wonder if that can really be a posisbility.

 

[chippie]

Re: Have you tried...

A mate had a similar problem, it was caused by the magnets in the cockpit speakers interfering with the unit's compass.