I'm having a problem with my KFC-150 autopilot not wanting to track a VOR or ILS/LOC while in the NAV or APCH mode. The flight director also does not want to display deviation from the course or glideslope. Both NAV heads (the HSI and the number 2 OBS) work normally. Pretty certain that a trip to the avionics shop is in the works but in the meantime does anyone have any good hints as to what I can do (keep it clean, please!) to track down the problem and failing that, any good recommendations for an avionics shop in the NJ, Delaware or Eastern PA areas?