What was found
AT FL 190 AND CLIMBING (310 KIAS) THE FIRE WARNING BELL & MASTER FIRE LIGHT WENT OFF CONTINUOUSLY WITH NO OTHER INDICATIONS. THE BELL WOULD ONLY SILENCE WHEN ANY SILENCING BUTTON WAS HELD IN. BELL AND LIGHT WENT OUT ON DESCENT, CAME BACK ON AS AIRCRAFT BLOCKED IN. BELL AND LIGHT WERE STILL ON UPON ACFT ARRIVAL, CONNECTED EXTERNAL PWR, DURING DEBRIEF WITH CREW, EXTERNAL PWR DROPPED OFF-STARTED APU, APPLIED PWR AND THE BELL AND LIGHT DID NOT COME BACK ON. COULD NOT GET THE PROBLEM TO DUPLICATE. T/S TO FIRE AND OVERHEAT DETECT OR ACCESSORY BOX IN E/E. REMOVED AND REPLACED FIRE DETECTOR BOX PER SMP'S. FIRE SYSTEM TEST NORMAL PER JRH CHAPTER 5 .