What was found
WHILE ACCOMPLISHING T/C 78273000 NR 1 ENGINE MAINTENANCE FAULT 73-31371, UPPER EGT SECTION READING HIGH ECONOMIC FAULT. ACFT GROUNDED. FAULT WAS FOUND ON FLT LEG 7. NO ACTIVE FAULTS FOUND AT THIS TIME. THIS FAULT IS INTERMITTENT. EGT READINGS AS FOLLOWS. S1 = 180, S2 = 126, S3 = 140, S4 = 199. DISCONNECTED AND INSPECTED CJ9 & CJ10 HARNESS DISCONNECTS AND ALL 4 T49.5 PROBE DISCONNECTS. FOUND BLACK RINGS AROUND PINS ON BOTH S1 & S4 PROBES. CLEANED ALL DISCONNECTS AND REPLACED BOTH S1 & S4 PROBES. OPS TEST GOOD. AFTER READING AS FOLLOWS, S1= 37, S2 = 22, S3 = 22, S4 = 47. REF FIM 73-11 TASK 801 AND AMM 77-21-01 FOR WORK PERFORMED. GROUND VERIFICATION GOOD.