What was found
SMOKE CARGO WARNING MESSAGE ON CLIMB OUT. COMPLIED WITH QRH, INCLUDING DISCHARGE OF HALON. RETURNED TO FIELD. NOTICED CB 1G1 POPPED OUT ON GROUND. FLT 4677 INSPECTED CARGO PIT & FOUND NO EVIDENCE OF A FIRE. CB 1G1, CARGO FIREX 2, POPS WHEN CARGO FIREX SYSTEM IS TESTED. REPLACED RELAYS K7HL, K5HL & K11HL IN JB10. PERFORMED OPERATIONAL CHECKS OF JB10 IAW AMM. ALL CHECKED GOOD AT THIS TIME INCLUDING THE FIRE CARGO SMOKE DETECTION SYSTEM PN M83536/6-025M & XE4N023.