Hi, Stuart, Lets start with the gypsies warning I always give,
Whatever happens please remember you are messing around in a piece of equipment that runs at 4000volts and due to the design of its circuitry under certain fault conditions it remains lethal months after having been disconnected from the mains supply. its not rocket science as they say, but it is not for the layman either. Contact me via microwave-repairs.co.uk if you need further help.
Ok, having said that, firstly how do you know the magnetron has failed ? if you know enough to answer that then you are probably capable of the rest.
Neff prices for spares are astronomical, nearly £200 for a Mag change that any competant dealer can do for half that.
Patrick, October 2010