How many fuses are there is this microwave? Is there anyway to check the magnetron? Another sympton I should add is that on the heating , the touch buttons - some work better than others. If we punch the 5 minute button and stop the oven after three minutes we get much more heating then if we use the 3 minute button, although probably still not as good as it should. The 1 minute and 2 minute don't work well either.