What was found
DEPARTED, DURING A SECOND CLIMB FROM APPROXIMATELY 13,000 TO FL 250, NR 1 ENGINE FIRE ANNUNCIATOR FLICKERED THEN STAYED ON CONTINUOUSLY ACCOMPANIED BY THE FIRE BELL. CANCELED THE BELL, AND RETARDED THE THRUST LEVER ON THE NR 1 ENGINE, PRIOR TO EXECUTING THE ENGINE FIRE CHECKLIST, PULLED BACK ON THE THRUST LEVER, THE ENGINE FIRE ANNUNCIATOR EXTINGUISHED. RETURNED TO DEPARTURE FOR MAINTENANCE. ALL ENGINE INDICATIONS NORMAL.