Autopilot Veers to Starboard when Set to Auto

[timj]

Hi

I'm seeking advice please. My Wagner Micropilot works very well once it is up and running. But when I set it from standby to active (auto) it immediately veers about 10 degrees to starboard before slowly returning to the set course. Thereafter it operates normally.

It is more an inconvenience than a major problem but I would like to fix it if possible?

The unit is about 20 odd years old and we replaced the motherboard last week. But the problem occurred
previously with the old motherboard before that died.

Any suggestions much appreciated. Someone suggested that it might relate to the rudder feedback which is called follow up transmitter (I think) in the manual.

Apparently Wagner micro pilots had a good reputation but are no longer made unfortunately.

[GMDSSMainainer]

95% of the time problems like this are related to a fault in the rudder feedback also known as the rudder followup. It is the device down below that is mechanically linked to the rudder stock. With these older units the whole device consists usually of a simple potentiometer. I would first measure the voltage being sent to it to make sure it's correct. If it is then I would cut power and measure the resistance from hard over to hard over and see if the transition is smooth on the multimeter. If it isn't, if it look "jumpy", that would mean that the pot has a "dead spot" and would need to be replaced. You may not be able to replace the whole feedback, but you may be able to just replace the potentiometer.

Of course that all depends on if this particular AP uses a pot to begin with. I am not familiar with wagner but most older units use a simple pot although some older ones, some simrad, use frequency signal instead of voltage.

[timj]

Many thanks. I will check it out today!