One thing I'd suspect is the cabling between the control head
and the motor
unit. The contacts may have developed a case of surface corrosion
which is blocking the feedback signal from the motor unit.
Also, I think you've seen my other post about the rudder
position indicating device (tiny generator
, turned by nylon gears, one of which is friction-fit to a stainless steel
shaft). If this little device isn't turning, there won't be any rudder position feedback.
Sorry, I gave all my spare parts
(including 3 circuit boards) away when I sold the autopilot
. If I remember correctly, I did once have a problem with the circuit board which is located in the motor unit. But, for many years I didn't recognize that the main problem was with the design of the rudder feedback device itself. Once I sorted that out (by drilling a hole in the hub of the larger nylon gear
and dimpling into the s/s shaft with a set screw), most of the problems disappeared.
However, this is a very iffy autopilot
. If you're planning to keep the boat you may want to plan for replacing this gear
sometime in the future.