As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING HEAVY MAINTENANCE, EPSU-EMERGENCY POWER SUPPLY UNIT DONT PASS OPERATIONAL TEST. REPLACED EPSU IAW AMM 33-51-38-400-001-A. PERFORMED OPERATIONAL TEST OF THE EPSU IAW AMM 33-51-00-710-001. TEST IS GOOD AT THIS TIME. SUPPLEMENTAL INFORMATION TO FOLLOW.