What was found
BOS FLT 750 EN ROUTE PHL TO BRU. PRIOR TO RECIRC FAN TWO OCCASIONS OF SMOKE AND FUMES 1. SWEET BURNING SMELL THROUGHOUT CABIN SHORTLY AFTER T/O. 2 STRONG ELECTRICAL SMOKE ABOUT 1 HOUR INTO FLIGHT. THE FLIGHT DECLARED AN EMERGENCY AND DIVERTED INTO BOS. THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE INSPECTED THE AIRCRAFT AND PLACED THE RIGHT RECIRCULATION FAN ON MEL. MAINTENANCE REPLACED THE RIGHT RECIRCULATION FAN. VENDOR SHOP FINDINGS: MODERATE CONTAMINATION/BEARINGS SEPARATED/BEARINGS SEIZED IN ENDBELL/ROTOR GROOVED/ENDBELL DISTORTED. PRIMARY FAILURE BEARING: CONDITION SEPARATED. REPLACED ENDBELL, ROTOR AND BEARINGS REPLACED 100%.