Autopilot problem

Lucky Duck

Lucky Duck

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Yesterday a friends's autopilot kept disengaging and then briefly displaying the message 'Sail 5000'. This kept happening at seemingly random intervals. For the last couple of seasons it has performed faultlessly.

Any ideas what the problem might be and possible solutions as the Raymarine help desk wasn't very helpful.

The installation is ST4000+ which has been upgraded with type 1 linear drive.
 
I have an ST4000 and not seen that problem - some others lol. But what I find interesting is that everyone seems to rave about the Raymarine helpdesk. I need to call soon with a Micronet MN30 prob.

What do you mean by "wasn't very helpful"?
 
Is the "Sail 5000" message the same thing as you see when you first power the unit up? I know you may not have seen it when it first starts if the on-off switch is situated below - once having turned on the display will be showing normal information by the time you get to it! But if it is the 'power-on' display I would suggest that the unit is dropping out completely, then resetting (hence the message).

Does it happen when the unit is in standby? If it only happens when in use I would suggest that you have a supply problem. Attach a multimeter firmly to the power input of the unit. Don't rely on just holding the probes into the connector, you want to make sure the probes make good contact. Note the supply voltage at rest. Get a pal to operate the head unit, requesting movements to port and stbd. Ask for the maximum you can so that the quadrant (I'm assuming you have one) is driven to the limit each way. Note the meter readings. They should not drop below the manufacturers published limits.

You may want to simulate adverse sea conditions by restraining the quadrant movement if you think it only happens, say in a following sea.
 
If you do find that the supply 'sags' when the ram is active (demanding more current) it's most likely that there is a connection somewhere in the supply wiring which has developed a higher resistance. Before you start pulling out all the wiring (!) you might want to run a temporary +ve supply to the controller and see if the sag still occurs. Then if that doesn't solve it, run a temp -ve line. Go straight to the battery, but remember this will be unfused in the case of the temp +ve. You might want to add a 30A inline fuse. A car one is fine. Doing this splits the fault location so you only have to trace on half the wiring. I'm sure you're aware already, but it's worth remembering to be really careful when poking around these high current areas. Nothing will go badly BANG but the fright can make you bang your head....... don't ask me etc etc etc
 
+1 to suspecting cable or connections including the spade connectors at the back of the AP unit (just pulling them off and reconnecting may fix it). If the cable is near minimum size for the length of run and is old and green it may need to be replaced. A flat battery will cause this too (don't ask).

Andrew.
 
Simon13b very kindly initially posted on my behalf

Just an update

We thought it was a power supply problem and checked all connections and applied a little wd40. On the return trip the autohelm was all ok, but we went back under genoa , so not really tested the autohelm.

Whilst at the boat today, with the boat sat in the marina, I turned the autohelm on, just to see what happened.

There was two oddities. Firstly, if I applied pressure to the tiller, to simulate some weather helm, the autohelm reset, but maybe this was due to too much pressure. Secondly, without warning, the tiller moved by some 20 degrees and then an error message came up "drivestopped", but did not reset, and remained on auto, I understand from the manual this is because either the rudder cannot move or the rudder reference unit was faulty. I also noted that sometimes the tiller was making constant corrections, even though the boat was not changing direction in the marina.

Any ideas anyone, seems very intermittent, which makes it hard. I was going to pull off the connections behind the control head but they were very firmly attached and did not want to do any harm
 
D&T said:
Simon13b very kindly initially posted on my behalf

Just an update

We thought it was a power supply problem and checked all connections and applied a little wd40. On the return trip the autohelm was all ok, but we went back under genoa , so not really tested the autohelm.
Click to expand...

You say you checked all the connections - did you actually measure the supply voltage? And did you check for 'sag' when the drive is engaged? Sorry to emphasise this, but supply voltage really is the first thing to eliminate. You say you have cleaned the connections but the problem may be in the wiring elsewhere!
 
+1 to measuring the voltage at the drive unit and at the instrument. The suspicion is that it is too low because of low battery, poor connections or damaged/corroded/"thin" cable - particularly under load. The 'sag' is the fall in voltage when the drive is working hard. A large fall could be due to any/all of the above faults plus a fault within the unit such as a damaged wire or dry joint to the motor.
The connectors behind the control head are the first ones to check - be careful and only hold them by the connector and not the wire. Just GENTLY wiggling them side to side with a small amount of WD40 may help if they won't come right off. If they do come right off be careful as you replace them to fit the male tang between the spade connector's "teeth" and not between the spade and the plastic sheath.
If you decide to open the drive unit up it is not too hard and I'd be happy to "talk" you through it - the first step is to unscrew the little "grommet" where the cable passes into the unit. If you PM me with an e-mail address I have written some notes that explain how to strip the unit right down - but check the connections and voltages first.

The little hunting movements within the marina should not be a problem as the unit searches for perfection. A large swing would be an issue.

Good luck, Andrew
 
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