What was found
NR 2 PRESS REGULATOR FAULTED OFF DURING CLIMBOUT TURNED SYS 2 OFF IAW ECAM. .5 MN LATER AVIONICS SMOKE, LIGHT AND WARNING OCCURED. LIGHT STAYED ON FOR DURATION OF FLIGHT. FOLLOWED "AVIONICS SMOKE" PROCEDURES IN QRH AND MADE EMERGENCY RETURN AND LANDING. NO SMOKE WAS OSERVED THRU THE SNIFFER FAN DURING FLIGHT T/S IAW FIM 26-15-00, FIG 102. FOUND MAIN BAY DUCT SMOKE DET 11WA FAULTING. R AND RED SMOKE DETECTION 11 WA IAW AMM 26-15-12-04 AND PERFORMED TEST IAW AMM 26-15-00-5 AND ALL TESTS PASSED. PERFORMED CABIN PRESSURE CTRL NR2 OPS TEST AND BITE TEST IAW AMM 21-31-00-05-0, ITEM (F). ALL TESTS PASSED PERFORMED UNDER OPS CHECK IAW AMM 26-15-00-05 AND ALL TESTS PASSED.