My 201 has a Century IIB Auto-pilot along with a Sys 60 PSS. Works OK intermittently so I can't depend on it for serious IFR flying. It performs OK sometimes, but it may suddenly lose its bearings and begin an oscillatory behaviour and deviate significantly from assigned Nav or Hdg and I have to disengage it. Same with the PSS, it may work fine for 15 minutes, then suddenly it will send the plane climbing or descending and I have to overrde it. Is it a matter of servicing or calibration? Any suggestions on shops in (Northern) California who might be experts on these systems? Thanks.
Sriram