As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RECEIVED REPAIRED SERVO AMP UNIT FROM LEARJET, REMOVED FROM BOX, UNIT OPERATED NORMALLY FOR 5 MINUTES AFTER WHICH TIME AN ELECTRICAL BURNING SMELL WAS EMITTED AND UNIT QUIT OPERATING. RETURNED SAME TO LEARJET FOR REPLACMENT. RECEIVED SECOND UNIT. INSTALLED ON AIRCRAFT AND RETURNED TO SERVICE. (PN 501-0005-01).