Robertson AP20 Autopilot Operating Erratically

[Uncle Buck]

My Autopilot has begun to do strange things. When first in use, it works fine, for as little as a few minutes to more than an hour. Then, all of a sudden the display will show the rudder position jumping around erratically (even though the rudder is stable), and then the boat's course goes haywire as I guess the control unit is thrown for a loop. If I shut the power off and the restart, it usually works fine for a short time again.

I went ahead and replaced the RF300 Feedback unit with a brand new one, but this made no change. I thought this was likely the issue since it seemed to make sense (and for a brief moment the display showed a " failure of RF unit " or something like that.)

Now I don't know what to do, and am wondering if the new RF unit could be defective? Or try a " Master Reset " ?

Thanks in advance for any help!

[r.furborough]

on this type of pilot, does the rudder feedback sensor not interface to the computer via an interface box. If so that could be the problem.

[svHyLyte]

Originally Posted by EvanStolze

My Autopilot has begun to do strange things. When first in use, it works fine, for as little as a few minutes to more than an hour. Then, all of a sudden the display will show the rudder position jumping around erratically (even though the rudder is stable), and then the boat's course goes haywire as I guess the control unit is thrown for a loop. If I shut the power off and the restart, it usually works fine for a short time again.

I went ahead and replaced the RF300 Feedback unit with a brand new one, but this made no change. I thought this was likely the issue since it seemed to make sense (and for a brief moment the display showed a " failure of RF unit " or something like that.)

Now I don't know what to do, and am wondering if the new RF unit could be defective? Or try a " Master Reset " ?

Thanks in advance for any help!

THis may come rather late in your game but we had a somewhat similar problem that turned out to be a loose wire connection at the computer. I disconnected the wire, cleaned up a bit of corrosion that had developed, reconnected the wire and applied a little dialetric grease for protection and we were good to go.

FWIW,,,

[donradcliffe]

In my case, the rudder indicator display was jumping around, causing some extra steering on the part of the pilot, but no major off-course maneuvers. Because I was in the middle of the Indian Ocean, I just rotated the RFU as far as it would go on its base and recalibrated. That got me to the next port, where I installed a new RFU and everything was fine. Now I keep the rudder off center when anchored, preventing the wear on the RFU at zero rudder angle.

Your case sounds like it could be the wiring, but did you buy a 'new' RFU on Ebay??

[Uncle Buck]

Originally Posted by donradcliffe

In my case, the rudder indicator display was jumping around, causing some extra steering on the part of the pilot, but no major off-course maneuvers. Because I was in the middle of the Indian Ocean, I just rotated the RFU as far as it would go on its base and recalibrated. That got me to the next port, where I installed a new RFU and everything was fine. Now I keep the rudder off center when anchored, preventing the wear on the RFU at zero rudder angle.

Your case sounds like it could be the wiring, but did you buy a 'new' RFU on Ebay??

That sounds very similar to my problem. I bought the new RFU from West Marine and installed it with the wiring supplied, but of course it is possible that either 1) the connection I made isn't solid or 2) the new unit itself is actually not new or is bogus......looking at the one that I took out it could easily be made to look as if it new. Do you think it's probable that I got a bogus " new " RF unit?

[donradcliffe]

Not too likely, and you should be able to check that the RFU is working correctly by watching your control panel rudder indicator as you swing the rudder back and forth.