Robertson AP200 Autopilot

[yachtsman7]

I have a Robertson AP200 Autopilot. After switching on, it steers my boat for about 30minutes and thereafter dives off course and each time I put it back on course it dives off course within a few minutes. This autopilot has a Coarse Computer and a hydraulic ram.

 

[saltwater_gypsy]

I too have a Roberstson AP200 but I don't know if I can help.
Some diagnostic questions.
(1)Set mode to PWR.ST
Can you steer the boat with the Course control?
(2)Set Mode to COMP.
Does the compass reading make sense?
(3) Do the dodge controls work?
(4) does it always fail to the same direction eg dive to port?
My system is electric but I would check the connections to the hydraulic control valves in case one direction is faulty.

 

[yachtsman7]

Thanks for advice, Iam launching on Wednesday so will try out your suggestions as soon as and I'll let you know the results.

Many thanks.

 

[Sequoiah1]

Have you checked the compass? Could be you have an anchor or some big bit of metal very close to it!

 

[yachtsman7]

Yep, nothing close that may interfere with it.