What was found
DURING PREFLIGHT POWER ON CHECKLIST, EMER LTS CHECK FAILED WHEN SWITCH POSITIONED TO ON AND NO LIGHTS ILLUMINATED. WHEN SWITCH POSITIONED TO ARM, ALL EMER LTS ILLUMINATED EXCEPT AFT BULKHEAD EXIT AND LOWER EXIT ON LAV FRONT PANEL. AS DIRECTED BY MCC, TWO ATTEMPTS TO CHARGE EMER BATT WITH 2X30MIN APU CYCLES UNSUCCESSFUL. RFMOVED ALL EMERGENCY LIGHTING BATTFRY PACK PN CBS28-1 SN 006945 AND REPLACED WITH REPAIRED CUSTOMER SUPPLIED EMERGENCY LIGHTING BATTERY PACK PN: CBS28-1 SN: 0774M IAW CE-680A MM 33-50-06. OPS CHECK GOOD