What was found
BOS - FLT 4512 - SHORTLY AFTER TAKEOFF, CREW RECEIVED A CARGO SMOKE WARNING. CREW FOLLOWED CHECK LIST AND DISCHARGED FIRE EXTINGUISHER BOTTLE AND RETURNED TO BOS WITHOUT INCIDENT. MX FOUND POWER WIRE GOING TO CARGO INTERIOR LIGHT HAD CHAFED ON SMOKE DETECTOR CAGE CAUSING SMOKE WARNING TO ACTIVATE. LIGHT WAS DISCONNECTED AND SYSTEM DEFERRED. FIRE BOTTLE WAS REPLACED AND AIRCRAFT RETURNED TO SERVICE. (M)