As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENANCE: DONT PASS EPSU TEST 13WL PN:3214-54-10 SN:5880 IN AFT GALLEY AREA. PERFORMED TROUBLE SHOOTING IAW TSM 33-51-00-810-801-A STEP 1 THRU STEP 3 ANDSTEP 4.B.4. MAINTENANCE REPLACED EMERGENCY POWER SUPPLY UNIT FIN 13WL IAWA MM 33-51-38-000-001-A, AMM 33-51-38-000-002-A, AMM 33-51-38-400.