Robertson Autopilot AP 100 DL

[omega2]

Any one out there with knowledge of these units? just recently when engaging the auto we hold course for about 10 seconds then we veer off to starboard, sometimes we check and revert after a 20 degree divergence but other times we carry on with helm hard over screwing ourselves into the ground. When used in power steering mode we can steer port and starboard using the red and green buttons no problem. For those who know these ancient pieces of kit, on switching to auto sometimes we get F67 fault code up (rudder feedback unit failure), this is removed by switching off and then back on again. When doing the circle we get F80 up telling us we are off course. Any ideas as to what we should be looking for appreciated.

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J HAMER

 

[pvb]

It does sound like the rudder feedback unit is playing up. Can you get inside it? Usually, it's just a potentiometer, and maybe the wiper contact needs cleaning/adjusting. If you don't have one already, you can download the manual here - and what a manual too, complete with wiring diagrams, they knew how to do manuals in olden days!

 

[Stoaty]

I am not familiar with your autopilot but it's almost certainly the pot in the rudder follow up unit on it's way out. They are cheap enough to buy from RS components but you will have to set it up with a digital meter so that the reading is zero ohms when the rudder is amidships. This is usually done with a screw set in the centre of the arm. You can test the pot by putting an ohm meter across the common and one of the other legs and operating it. The increase and decrease in resistance should be smooth when operated and when on zero ohms if you measure the resistance between the other leg and common it too should read zero.

Hope that's not to complicated.

 

[boatmike]

Check the rudder feedback unit wiring. The unit itself will probably be mounted on the rudder quadrant and often this is a damp place where corrosion and wiring problems are not obvious. If it is not giving a feedback signal to the box then the computer thinks the rudder has not moved and will continue to tell the actuator to put on more rudder.

 

[omega2]

Thank you all for your assistance, you have confirmed my suspicions, as when doing the self test I am unable to get P000 or S000 readouts, are these pots interchangeable and/or servicable?