What was found
FLIGHT 2706 - GSO - FLIGHT CREW REPORTED DURING CLIMBOUT LOST PFD NR 2, MFD NR 1, RRMU NR 2, TRANSPONDER, RA ON EICAS MESSAGE. PFD NR 2, FMS NR 2 ALSO WAS LOST. AVIONICS SWITCH LIGHT ON DESCENT. CREW PERFORMED AIR RETURN AND LANDED AIRCRAFT UNEVENTFULLY. MX CLEANED AVIONICS MASTER SWITCH NR 2 AND PERFORMED OPERATIONAL CHECK SUCCESSFULLY. AIRCRAFT WAS APPROVED TO RETURN TO SERVICE.