What was found
ABOUT 1 HOUR INTO FLIGHT AT FL340, NOTICED A BURNING ELECTRICAL ODOR ALONG WITH VISIBLE "HAZEY" SMOKE IN COCKPIT. COMPLIED WITH QRH. AFTER SECURING PACKS AND CABIN BUSS SWITCH, SMOKE AND ODOR SEEMED TO SUBSIDE. BURNING ODOR WAS DEFINITELY ELECTRICAL. REMOVED AND REPLACED AVIONICS RACK COOLING FAN CONTROL RELAY R2-5895 OPS CHECK OF NR 1PACK FAN NORMAL PER 21-26-02. AS PER CONFERENCE CALL WITH MOCC, RAN ALL 3 ENGINES WITH PACKS 1,2, AND 3 RUNNING USING ENGINE AIR. ALSO, HAD ENGINE GENERATORS POWERING ACFT. NO NOTICEABLE ODORS IN COCKPIT. RAN ENGINES AS PER JRH.