What was found
AT FL 330, CREW EXPERIENCE BRIEF FIRE WARNING OF 2 RINGS AND LIGHT IN HANDLE ON NR 1 FIRE HANDLE. WARNING WAS OUT BEFORE RESET WAS PUSHED ON FIRE WARNING LIGHT. FIRE WARNING TEST WAS DONE TO ALL 4 ENGINES TO CONFIRM NO FIRE PRESENT. AT THE TIME NR 1 OIL TEMP WAS 131 DEG C. NR 1 THROTTLE WAS REDUCED TO FLIGHT IDLE AND OIL TEMP CAME DOWN TO 120 DEG . RETURNED THROTTLE LEVER TO NORMAL CRUISE, OIL TEMP STABILIZED AT 110 DEG ALL ENG INDICATION NORMAL. REMOVED AND REPLACED NR 1 FIRE DETECTION SYSTEM AMP. NR 1 ENG FIRE WARNING OPS CHECKS GOOD.