Autohelm (Raymarine) 4000 autopilot wandering
Posted: Sat 26 Sep 09, 18:57
I had a problem with my 4000 autopilot changing course as much as 20-90 degrees all by itself.
If left alone, it would gradually correct itself, but of course it was not acceptable.
After checking all the wiring connections (even opening up the fluxgate compass to check) I finally found the problem.
In the center of the display circuit board are four power transistors mounted on a heat sink.
Two turn the wheel starboard and the other two turn it port.
Over time, the heating and cooling of these parts had caused microscopic cracks in the solder connections, and thus the problem.
Out of twelve connections I found and resoldered NINE bad ones !
Now my autopilot tracks perfectly (both by compass and apparent wind) and as an added bonus it corrects a lot less, thus saving electricity.
Steve B.
If left alone, it would gradually correct itself, but of course it was not acceptable.
After checking all the wiring connections (even opening up the fluxgate compass to check) I finally found the problem.
In the center of the display circuit board are four power transistors mounted on a heat sink.
Two turn the wheel starboard and the other two turn it port.
Over time, the heating and cooling of these parts had caused microscopic cracks in the solder connections, and thus the problem.
Out of twelve connections I found and resoldered NINE bad ones !
Now my autopilot tracks perfectly (both by compass and apparent wind) and as an added bonus it corrects a lot less, thus saving electricity.
Steve B.
