As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FAILED ENCODER REMOVED AND REPLACED. NEW ENCODER FAILED TO WORK. FOUND THAT WHILE BOTH UNITS HAD THE SAME PART NUMBER (0900-4099-01), THE NEW UNIT IS NOT PLUG COMPATIBLE. SUBMITTER SUGGESTS AN UNDOCUMENTED DESIGN CHANGE BY THE FACTORY IS THE CAUSE OF THIS PROBLEM.