What was found
PRE-DEPARTURE CREW REPORTED MAIN CARGO FIRE INDICATION WITH SMOKE SMELL. POSITIONS 8 A AND B GREEN LIGHTS ANNUNCIATED. 8A TURNED AMBER, 8B EXTINGUISHED. EMERGENCY DECLARED AND AIRCRAFT GROUNDED. TO FACILITATE MAINTENANCE, CARGO FREIGHT UNLOADED. FAULT ISOLATED TO APU BATTERY AND BATTERY CHARGER. REMOVED AND REPLACED APU BATTERY AND CHARGER IAW B767 AMM 24-31-04/05. OPERATIONAL CHECKS GOOD. GENERAL VISUAL INSPECTION OF APU BATTERY AND CHARGER WIRING SATISFACTORY IAW SWPM 20-10-06. AIRCRAFT RELEASED TO SERVICE.