What was found
JUST AFTER TAKEOFF, FO TUBES WENT BLANK, LOST WX RADAR, TCAS, GPS, NAV, COM 2. LOOKED UP AT PANEL AND NOTED R MAIN AND R ESS BUSS LIGHTS ILLUMINATED. CREW DECLARED AN EMERGENCY AND RETURNED TO MEM WITHOUT FURTHER INCIDENT. CREW CYCLED CIRCUIT BREAKER "R ESS R MAIN" AFTER LANDING AND OPS RETURNED TO NORMAL. CYCLED A/C POWER AND TESTED ELECTRICAL SYSTEM REF AMM 24-30-00-05 AND 24-20-00-05. INSPECTED RT PDU AREA AND REPLACED TRANSIENT SUPPRESSOR RDI 56P1CR1 PN: 7239790-501 FOR PRECAUTIONARY REASONS. RAN A/C AGAIN AND VERIFIED NORMAL OPS. ALL CIRCUIT BREAKERS REMAINED IN THROUGHOUT TESTING AND TROUBLESHOOTING.