What was found
DURING CLIMB AT FL 170 NR 1 ENG (B) LOOP LT ILLUM WITH LOOPS LT ON MWP. CHECKLIST CARRIED OUT AND ENG FIRE WARN REMAINED ON AFTER POSITIVE TEST OF LOOP (A). INFLIGHT ENG FIRE PROC CARRIED OUT AND A/C RETURNED TO HONG KONG. NOTE: FIRE WARNING CEASED WITH FUEL LEVER IN (OFF) POS. ENG FIRE AGENTS NOT DISCHARGED. INSPECTED ENG NO LEAKS FOUND. FOUND LT UPPER CORE (B) LOOP OPEN CIRCUIT. IAW A300 MEL 26-12-01 CAT B TRANSFERRED TO DMI NR 3526. FOUND BROKEN WIRE ON NR 1 ENG UPPER "B" LOOP FWD CONNECTOR. REPAIRED WIRE IAW A300 AWM & AMM 70-71-12. OPS CK GOOD. THIS ACTON CLEARS DMI 3561, PLACARDS REMOVED.