What was found
CREW REPORTED-IC 600 1 FAIL IN FLIGHT LEVEL 340. LOST ASSOCIATED SCREENS (PFD1, MFD1, EICAS) AND AUTOPILOT. RAN QRH PROCEDURE AND RETURNED TO DAL. CORR ACTION- MX PERFORMED SYSTEM RESET AND RERACK OF IC-600 #1 SYSTEM OPS TESTED GOOD. HAS FLOWN THREE 3 LEGS SINCE NO FURTHER ISSUES NOTED.