GE spacemaker xl1800 and Pop tarts bad mix

Question

My son put his pop tart in the microwave with the foil still on and you know it smoked made noise etc. Now the microwave will not heat at all. All parts work turn table turns lights come on but no heat?? magnatron, board or voltage dohicky?I can check voltage and or test continuity if needed.....ANSWER: more than likely the fuse has blown onthe magnatron it is the button looking thing on the magnatron with two wires. there are 2 of these one is on the magnatron the other is above the heat box test these for open. if open replace. if good then replace the magnatron.OK I replaced open fuse, hooked everything back up and now the fuse is blown again? does this mean I have a magnatron problem? I rechecked all the other fuses and they are good.. Thanks