jimbo,
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.
Good luck,
Bill