What was found
IN CRUISE, FLIGHT CREW HEARD A NOISE COMING FROM FORWARD PART OF FLIGHT STATION (RUMBLING NOISE), THEN DETECTED FUMES (ELECTRICAL) AND WENT THRU SMOKE ELIMINATION AND AVIONICS SMOKE COM PROCEDURES. DIVERTED INTO STL, DECLARED AN EMERGENCY AND LANDED UNEVENTFULLY. BLOWER FAN FOUND FAILED, SWAPPED UNIT WITH EXTRACT FAN, EXTRACT FAN PLACED ON MEL 21-26-02A.