What was found
AFTER TAKEOFF, APPROX 40 MINUTES INTO FLIGHT, AC TURNED BACK DUE TO NAV PROBLEMS WITH GPS SYSTEM. GPS SYS NR 2 PREVIOUSLY MEL, NR 1 GPS SYS WENT TO DR MODE. AIRCRAFT RETURNED TO BASE, NORMAL LANDING ACCOMPLISHED. MX CLEANED AND RESET CONNECTION ON GPS ANTENNA CONNECTOR IAW 34-58-11. THIS ACTION CLEARED NR 2 GPS MEL AND CORRECTED NR 1 GPS SYS GOING TO DR MODE. SYSTEMS OPERATES SATISFACTORY, AC RETURNED TO SERVICE. (K)