What was found
CARGO SMOKE WARNING LIGHT ILLUMINATED DURING CLIMB. LIGHT REMAINED ON FOR 5 SECONDS THEN WENT OUT. LIGHT ILLUMINATED AGAIN THEN WENT OUT. AIRCRAFT RETURNED TO SEA AND LANDED WITHOUT FURTHER PROBLEMS. NO SIGNS OF SMOKE OR HEAT NOTED. BROKEN WIRE AT NUMBER TWO SMOKE DETECTOR. CANNON PLUG REPAIRED, NUMBER ONE SMOKE DETECTOR REPLACED AS A PRECAUTIONARY MEASURE, UNIT WAS SLOW TO TEST. SYSTEM OPS CHECKED GOOD.