As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE UPGRADING VOLTAGE REGULATOR P/N 68804-006 TO P/N 68804-007 IAW MFG SERVICE LETTER 1049 WE HAVE HAD SEVERAL NEW REGULATORS THAT WOULD NOT WORK RIGHT OUT OF THE BOX. IN THIS PARTICULAR INSTANCE THE REGULATOR OPERATIONAL CHECKED NORMAL DURING GROUND RUNS BUT IN FLIGHT CAUSED THE AUTO-PILOT TO FAULT. WE RECCOMEND DOING A THOROUGH JOB OF TESTING AUTO-PILOTS AND AVIONICS WHEN DOING THIS UPGRADE BEYOND THE SCOPE OF NORMAL GROUND CHECKS.