What was found
SMOKE ODOR IN COCKPIT, FIRST TIME, 530FL, & 350, ONE HOUR LATER, THIRD TIME 350. NO PHYSICAL SMOKE SEEN, SMOKE ODOR SEEMED TO DISSIPATE. DURNG TROUBLESHOOTING, FOUND ABNORMAL METAL ON METAL SOUND COMING FROM THE AVIONICS VENT EXTRACT FAN. REMOVED & REPLACED THE AVIONIC VENT EXTRACT FAN IAW AMM 21-26-51. OPS CHECKED GOOD. INSPECTED THE AIRCRAFT IAW TSM 05-50-0-810-831-A. NO SMOKE ODOR DETECTED. OK FOR CONTINUED SERVICE