What was found
MEM - FL1129 - FLT HAD BE RELEASED WITH AN MEL ON THE NR 2 ENG 'A' FIRE WARNING LOOP. EN ROUTE TO IAH, CAPT RECEIVED A FAULT IND ON THE NR 2 ENG 'B' FIRE WARNING LOOP. CAPT AGREED TO DIVERT TO MEM WHERE THE FLT LANDED W/O FURTHER INCIDENT. MX CLEANED AND TIGHTENED THE LOOP DETECTORS ON THE NR 2 ENG AND THE SYS CHECKED GOOD. THE A/C WAS THEN RELEASED WITH THE MEL DELETED. ON THE NEXT FLT, DURING CLIMB, THE NR 2 ENG OVERHEAD IND BECAME INTERMITTENT THEN STEADY. THE CREW ACCOMP SPECIAL PROCEDURES AND THE LIGHT EXTINGUISHED. FLIGHT RETURNED TO FIELD AT MEM AND LANDED W/O FURTHER INCIDENT. MX FOUND A PLATE ON TOP OF THE NR 2 ENG COMPRESSOR SECTION MISING. REPLACED SAME.