the top oven fan is the cooling fan.you need to pull the cooker out and remove the top panels only.you will see the silver round cooling fan and motor.sometimes greasing them can help but if not a new one will be required.held with 4 screws and to electrical connections.easy fix!
ck, January 2011
see if the back wall inside the oven comes off (SCREWS) or try takeing the back cover off , have all the power off when working on it, the nut holding the fan blades on , might have unwinded ..
