What was found
NR 1 AND NR 2 FMS BECAME UNRELIABLE AFTER APPROX 2HRS INTO FLIGHT. NR 1 AND NR 2 FMS INOP, PLACARDED AS SUCH PER MEL 34-37-, CAT D, DMI NR'S NR 1 D7575041-1853 AND NR 2 D7575042-1854, DUE 24 SEP 99 PLACARDS INSTALLED. NR 1 FMS, CLEANED CANNON PLUG ON DADC. OPS CKS NORMAL AS PER MM 34 ON GROUND FOR 3 HRS THIS CLEARS MEL34-37 NR 2 FMS. CLEANED CANNON PLUG ON DADC. OPS CKS NORMAL ON GROUND FOR 3 HRS AS PER MM 34 THIS CLEARS MEL 34-37 CONT NR 7575042-1854. REMOVED PLACARD.