As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAIN EXIT SIGN/LIGHT: MAIN EXIT LIGHT SIGN WONT ILLUMINATE . REMOVED THE #1 EMERGENCY POWER SUPPLY BATTERY PN: CBS28-1, SN: 5261M DUE TO INTERNAL FAILURE. INSTALLED REPAIRED UNIT PN CBS28-1 SN 008979 IAW CE680A AMM 33-50-06. POWERED UP AIRCRAFT AND CHARGED PACK AS REQUIRED. OPS CHECKS GOOD. CLOSED UP ACCESS AND SECURED AIRCRAFT.