As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT IN BASE MAINTENANCE: WHILE PERFORMING OPERATIONAL TEST OF EMERGENCY POWER SUPPLY UNITS, FOUND CIDS1 SHOWS CLASS 1 FAULT FOR BAT/EPSU (10WL) FWD L. MAINTENANCE REPLACED BATTERY FOR EMERGENCY POWER SUPPLY UNIT 10WL AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 33-51-38 WITH NO FAULTS NOTED.