What was found
GRINDING NOISE AND HOT FRICTION SMELL FROM FRONT LOWER FRONT OF AIRCRAFT. LASTED 2 MIN THEN UPON INSPECTION FOUND VENT BLOWER FAN 20HQ VIBRATING WITH STRONG ELEC SMELL IN MAIN AVIONICS BAY. ITEM HAD HISTORY OF CB TRIPPING EARLIER THIS MORNING. SMOKE FORM ATTACHED REMOVED AND REPLACED AVIONICS VENT BLOWER IN REF AMM 21-26-51, OPS CHECK TEST OK REF AMM 21-26-00 PARTS USED: 40-0597-3-0412,QTY :1 31-2126-9-9004,QTY :1 ROTABLE PARTS CHANGE WAS INDICATED - TT # 1339814 SN OFF 2242 FAN, AVIONICS F OFF 31-2126-9-9004 2242 ON 31-2126-9-9004 3050