As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTED THE COMPASS CARD DID NOT MOVE IN THE FREE OR SLAVED MODES WHEN THE AIRCRAFT WAS TURNED. REMOVED AND REPLACED DIRECTIONAL GYRO. SUBMITTER STATED THIS IS THE FOURTH TIME THIS GYRO HAS HAD THIS PROBLEM REPORTED (DIFFERENT AIRCRAFT). ALL SHOP VISITS HAVE RESULTED IN 'NO FAULT FOUND'.