What was found
IN CRUISE AT 360 APPROXIMATELY, 1 HOUR OF FLIGHT , FLIGHT CREW SMELLED STRONG CHEMICAL/PLASTIC DOOR . FLIGHT ATTENDANT SAID OVEN HAD BEEN ON, ODOR DISSIPATED SOME WHAT, BUT RETURNED THE REMAINDER OF THE FLIGHT AND AT GATE. AIRCRAFT WAS GROUNDED. REPLACED AVIONICS FAN 20HQ IAW AMM 21-26-51.