Raymarine Autohelm - multiple problems?

[bobnlesley]

I’m hoping that someone might be able to shed some light on what seems to be multiple failures/problems with our Raymarine Autohelm; contacting my ‘local’ Raymarine Specialist is not an option as we’re in the boondocks of Fiji.

To begin: We have a very basic 12Vsystem with an ST6000 Control unit, fluxgate compass, rudder reference unit and linear drive, all coming together via a type100 computer, no bells or whistles. The unit’s not heavily used as we’ve a windvane self steering unit as first choice but three days ago it working fine and yesterday when we powered it up it was ‘dead’; in between the boat hadn’t moved and we can think of no maintenance job we did which could have possibly had any effect on the systems components.

With a ‘dead’ system I began by checking the supply from the power switch to the computer and found a blown fuse in the computer – result!
Sadly not, even when the fuse was replaced there was power going into the computer’s cable bar, power also at the ‘Seatalk’ terminals, but still none reaching the ST6000 controller? Using a new cable to connect the Computer’s Seatalk terminals to the ST6000 Controller this problem too was overcome, though whilst the cable I used was a similarly sized 2-wire & copper screening cable, I suspect that it’s not a ‘genuine’ Raymarine cable as one wire is blue whereas the Raymarine one’s yellow; are the units ‘picky’ about this cable?.

So, we got power to the Controller but found it was still ‘dead’, never mind, we had a spare controller that another yacht gave us a year or two ago – no idea of it’s history – and wired that one in instead; it wasn’t ‘dead’ but no better; this one still didn’t light up, but it did give out a continuous squeal/buzz when powered up; bugger! Still not defeated, we had a third unit which we switched out a few years ago – it was working OK then other than the ‘standby’ button had failed, so the only way to stop the autohelm operating was to turn off the power This one did light-up and said ‘ST6000’, but only for about five seconds whereafter it beeped and changed to ‘ST Fail’, We’ve disconnected/reconnected all the wiring several times but can’t get anything else out of it; if you leave it alone it re-beeps every minute or so, but simply to say ‘ST6000’ for a few seconds, before returning to ‘ST Fail’

Looking around the internet searching ‘ST Fail Message’ I saw comments suggesting that: If the controller’s buttons ‘beep’ then it’s a computer/wiring problem, if they don’t ‘beep’ it’s a controller problem? Not really conclusive for me as the ‘Auto’ button beeps, though the rest are silent?

So whilst standing idle for a few days we seem to have suffered a blown fuse, a failed computer to controller cable and the controller itself has died; any suggestions as to where/what I can try next, or even just a suggestion as to what could’ve caused this catalogue of problems?

[S/V Adeline]

Blown fuse suggests some type of power surge on that circuit. Assuming you did not perform maintenance on any part of the electrical system, I would begin tracing down ground wires to verify nothing is 'loose'. A partial ground can increase current (blowing the fuse) and/or cause some electronics to perform erratic.

Are all other electrical devices operating properly?

[bobnlesley]

Originally Posted by S/V Adeline

...Are all other electrical devices operating properly?

Yes, everything else id fine..

[S/V Adeline]

Originally Posted by bobnlesley

Yes, everything else id fine..

The reason I asked is I have encountered multiple non-related systems, randomly erratic behavior or malfunctions which turned out to be traced to a loose 'common' ground. When 'loose' (isolated from battery ground circuit) it became a floating ground where one system was acting as the ground field for a completely separate system. This could explain a blown fuse in a circuit that wasn't being used. It was just a thought.
Looking forward to more input from others

[maine50]

If your controller is at your helm or some other place connected by RM connectors, disconnect the controller at the computer. Connect the controller to the computer AT the computer using a a made up cable using female spade terminals
on 3 wires. You might find the controller cable is bad.

[AndyEss]

Are you getting your "STfail" message in Standby or Auto mode?
My 300 computer threw a Fail message after a relay failed inside the computer. I also had a blown fuse.
I picked up another 300 and a 100 computer on Ebay. The Ebay 300 didn't work, but the 100 did.
I came up with an external relay bridge circuit to offload the 100 computer internal relays to safely drive my Type 2 linear drive. This same bridge can offload a 300 computer also.
The internal relays of the 300 are the only difference between it and the 100 computer.
My bridge will protect either the 100 or 300 computers by offloading the mechanical internal relays. The internal relays, with an external relay bridge, only provide a low power signal to drive the external relays. As originally designed by Autohelm, the internal relays have to drive the high power circuits that run the linear (or other ) rudder drive.
Once you get your AP working, feel free to contact me (PM) if you want my external relay bridge. This should greatly prolong the life of any 100/300 series Autohelm AP.

[captainjim47]

A "surge" is something usually associated with the power grid... not DC boat wiring, unless it is what you call an anomaly you don't know anything about. A voltage spike on a DC circuit will rarely blow a fuse, duration not long enough... esp. For a A/P circuit which should be slow blow. Most units are equipped with a strip of terminals for all significant connections, didn't see where that point in the system was tested good? When the fuse is replaced does it blow again?

[Howler]

I had very similar issues with a ST4000+ and spent a lot of time troubleshooting the controller and circuitry upstream. It turned out the connector to the drive motor on the helm was the culprit. Check connections and cables between the controller and the drive motor. Also check the drive motor itself with an independent power supply.

[doug cusick]

in fiji contact Baobob marine they are a raymarine dealer eiter vuda or denerau marina

[Mikado]

Give this guy a shoutout

Dan Gerhardt
C250@mydurango.net

He’s an expert on older Autohelm Raymarine systems

[S/V Adeline]

Originally Posted by captainjim47

A "surge" is something usually associated with the power grid... not DC boat wiring, unless it is what you call an anomaly you don't know anything about. A voltage spike on a DC circuit will rarely blow a fuse, duration not long enough... esp. For a A/P circuit which should be slow blow. Most units are equipped with a strip of terminals for all significant connections, didn't see where that point in the system was tested good? When the fuse is replaced does it blow again?

A 'surge' in a DC system usually refers to amperage, as most DC fuses are rated upwards of 240v. The most common would be a short circuit which allows amperage to surge to whatever the DC source is capable of producing giving the limitations of the circuit itself until something melts.

[Martkimwat]

Just a thought but, have you had an electrical storm in the last few days, since the last time it worked? have you checked the rest of your electronic equipment and compasses to see if they are all OK? A lightning strike on or near the boat could cause a surge.

[terrysandling]

We have just arrived in Gibraltar after a Atlantic crossing on a oyster56, had exactly the same problem, we found ever so often the auto helm would stop and go from auto to manual in force 6 to 8 winds we had to be quick to get to the helm to stop a jib, the fluxgate compass would also show a 180 degree turn on the chart plotter, when I went to first time to see what was wrong it was a blown fuse, we put a new fuse in and all was ok, however, when the auto pilot keep stopping we seemed to notice there could be a correlation between the freezers and fridges all coming on at the same time giving a electrical surge, one other point when I went to the fuse box and touch all fuses it was noticed that as I touched one fuse it was slightly loose in its holder ,when we accidentally touch it a small bleep sounded and all electronics retuned to normal, kind regard Terry

[Neptune's Gear]

Sounds to me like the drive unit has failed/is drawing too much current. Disconnect the drive and try again. Put a multi meter on the motor connection cables and make certain that the polarity reverses when you try to manually steer with the AP. If that works, check the condition of the drive unit motor brushes and bearings.....

[bobnlesley]

Originally Posted by doug cusick

in fiji contact Baobob marine they are a raymarine dealer eiter vuda or denerau marina

Yes I spoke to Baobob on the phone. Whilst they're the local 'Approved Supplier' and could no doubt sell me a knew one, but when it comes to fault-findin and repairs sadly, they appear to have less idea than I do