What was found
CLIMBING THROUGH 16000 FT GOT RED ECAM "ENG 1 FIRE" FOLLOWED ECAM AND QRH. NR 1 AGENT WOULD NOT DISCHARGE, USED NR 2. FIRE WARNING LIGHT STAYED ON THROUGHOUT FLT. MADE EMERGENCY RETURN. UPON ARRIVING AT AIRCRAFT, FIRE WARNING STILL ACTIVE, HANDLE LIGHTS ILLUMINATED AND A AND B LOOP FAULTED. FIRE DETECTOR CONTROL BOX SHOWED FAULTS ON BOTH LOOP A AND B. REMOVED AND REPLACED NR 1 AND NR 2 FIRE BOTTLES ON NR 1 ENG PER A300-600 MM 26-21-15-4. REPLACED SQUIBS ON EACH BOTTLE PER A300-600 MM 26-21-13-4, CONNECTORS OFF ON SQUIBS AND PSI SWITCHES FOR BOTH BOTTLES, ALSO REQUIRE SAFTEY WIRE. REMOVED/REPLACED NR 1 ENG FIRE DETECT CONTROL UNIT PRECAUTIONARY PER MM 26-12-11-4 OPS CHECK NORMAL.