Need help w old BH autopilot

[Flora]

Hello. I have a WH P-3C on my sailboat the has worked well until yesterday. When I engaged the AP it wouldn’t hold course - it started to wander off to port. After a few retries, I noticed that the rudder angle indicator on the remote was pegged all the way to starboard. Since then I’ve checked the mechanical attachment on the RAT to be sure it’s at 90 degrees when the wheel is centered; I’ve checked the electrical connections for corrosion and tightness; I’ve checked for frayed wires; I’ve tried making adjustments via the yellow POT; and I’ve gone through the entire set-up and adjustment process. Nothing changes the problem.
Any guidance is appreciated.
Thank you