Autopilot problem on my voyager

My autopilot went crazy this weekend. It still works but the compass gives on correct readings. So needless to say when it engages it takes you anywhere it wants to. It is a ray 650 that most of the voyagers had. Any thoughts on what to look for would be appreciated. And no, I did place anything new by the flux gate. Thanks for any thoughts.

By it works I mean it is not DOA. It engages, the pump works when you tell it to turn it turns, it just doesn't straighten back up. It just keeps turning. I tried a re calibrate and it was all over the chart. As I was doing a 360 degree circle the readings was from 10 to 180 off. The funny part is the way I was turning the reading was climbing. When it hit about 190 it started falling although I was still turning in the same direction. I wonder if the flux gate compass can go bad.

I'll do that tonight when I get down there tonight.

All good thoughts. I really didn't think the rudder feedback would be it bu like you say it's worth a check. The fluxgate is in the bilge under the master bead and I checked it and it looks fine. No screws put in anywhere. The only work I have done is remove the VHF 2 weeks ago but that's a couple feet from the course computer. I will check all the C/C wires though I case one of them could have been bumped or is loose. I changed the C/C last year. Old one went DOA. Bought a used one on eBay since they are no longer made. I really like this autopilot. This is the second boat with this unit and it usually works real well. I may have to replace it with a new one but I hate to spend 2 grand if I can get this one working again. Not impressed with Raymarine tech support. They have a number but don't seem to answer it or return calls. By the way, it is a 1999 vintage. I know it is 15 years old but I like the unit so if I can fix it that is my preference.

Good point. I already did that. It is working fine. Fluxgate or loose wire is looking likely.

I had the same problem on my last boat. So I don't think is that case. It has worked fine all along. He just started going nuts about two weeks ago. And it goes nuts all the time.

Update. I went to the lake this weekend. I believe I narrowed it down to the fluxgate. I tightened all the screws on the coarse computer. Fussed with the splices in the wire at the C/C. And installed the VHF radio back in place. I don't know what removing the VHF could have to do with it but that's when the trouble started. As of right now, everything is working perfectly again. Took a 30 mile trip this weekend and used the autopilot the whole time and it worked flawlessly. I don't know exactly what did it but it is working. I have ordered a new fluxgate compass just in case it acts up again. Let's hope it doesn't.

Good point. I'll do that

I bought a used fluxgate compass on eBay and replaced the old one this weekend. Problem solved. Appear toy the old fluxgate was going out. Works perfect now.