What was found
AFTER TAKEOFF, FIRE WARNING NR 1 ENGINE. ENGINE SHUTDOWN WITH ENGINE FIRE CHECKLIST. DISCHARGED BOTH LEFT WING FIRE BOTTLES. AIRCRAFT RETURNED TO SJU AND MADE OVERWEIGHT LANDING, BLOWING NR 1, 2 AND 8 TIRES. FALSE FIRE WARNING, NO VISUAL INDICATION OF FIRE. TROUBLESHOOTING NOTED FAULTY FIRE WARNING AMP. REMOVED AND REPLACED AMP SYSTEM, OPS CHECKED NORMAL. PERFORMED OVERWEIGHT/HARD LANDING INSPECTION, NO STRUCTURAL DAMAGE NOTED. REMOVED AND REPLACED NR 1, 2, 7 AND 8 TIRES, CLEANED ENGINE, REMOVED AND REPLACED NR 1 AND 2 FIRE BOTTLE.