As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE REPLACING EMERGENCY LIGHTING BATTERY PACKS WORKCARD 3351- 2991, FOUND RT EMERGENCY EPSU UNIT FAULTY DURING TEST FROM TEST BUTTON ON THE UNIT & PTP (110RH) AT LOCATION EXIT DOOR 606 (EMERGENCY). R & R EPSU UNIT IAW AMM 33-51. OPS CHCKD GOOD. NO FURTHER DEFECTS NOTICE AT THIS TIME. ACFT OK FOR SVC. (LP: 9570231, AIRCRAFT WAS GROUNDED)