Some of those whirlpools the mag could be removed with a little fanagling out the front behind control.if not you'll have to drop it down and remove the case be sure to discharge the cap by shorting across it with a good insulated screwdriver or needle nose once the case is off you may have to remove transformer or fan motor schroud or whatever is in your way so it will drop down its held on by 4 screws or nuts

Your eyes will light up and say "TILT".....It's very dangerous working on a microwave unless you discharge the capacitor as it will store energy, many deaths have happened from Joe Public crackin open a microwave and getting electrocuted cuz he didn't know what the hell he was doing