Shout out to Marine Electronics of the Outer Banks, who specialize in repair and resale of earlier Simrad products, amongst other electronics. They took delivery of my AP11 control head, charged 2 hours at $95/hr to clean and repair buttons, bridged some other items they identified as potential problems, and repaired the casing. Shipping back brought total to just over $200.
Having the buttons repaired allowed me to identify an issue with the rudder position sensor, which I replaced with Teleflex AR4502SI (important to get the 'SI' version for Simrad compatibility), which was a pretty easy install for my boat, F225 four strokes.
Follow the instructions re-calibration of autopilot, and adjust compass offset to substantially match binnacle and MFD navigation GPS, and we're back in business for around $500. Not that I wouldn't have loved to upgrade to a newer autopilot system, but if I have to flip a coin between new autopilot and adding radar in the spring, I'm happy to have the original unit back up and running reliably!
Bob.