No promises, but the most likely cause is the main oven fan motor. Disconnect the cooker from the electrical supply, and open the back. The oven fan motor will be visible in the middle of the back of the oven. Pull the two or three wires off the fan motor (make sure you mark which is which, so you can put them back later) and switch the cooker back on. If the fan was at fault the breaker will not trip, even if you turn the oven on long enough for the fan to start, if it were connected.
If that fixes the problem, do not reconnect the fan. Disconnect the cooker again and check the copper windings on the motor - they may be burnt. If you have a resistance meter, measure the resistance between one of the tags that connect to the windings and the metal motor body. It should be open circuit - too high for the meter to measure. The same should be so for the other tag and the motor body. If not, then a new motor is needed. If you leave the fan disconnected and the loose wires taped back on themselves, you can put the back on the cooker and use it - but not the main oven - until the new part is fitted. If you are in any doubt about electrical safety, get a friend who knows to help. Good luck.
PS if the breaker still trips, then disconnect the other fan and rotissary motors one at a time, switching the cooker off when touching the wiring. You may find the faulty part that way. If that fails it may be an element, so disconnect them in turn. When the breaker doesn't trip - you have found it. Make sure you draw a diagram so that you can put the wires back on afterwards.
Bern, October 2008
