Hi,Welcome to Just Answer, My name isXXXXX will be helping you with your appliance issue today.
your high voltage transformer is overheating. the problem is its no longer available from what I can see, your better off replacing the microwave at this point, in fact most of the parts are unavailable for this unit. you would be wasting your money having a service tech look at this and tell you they cant get the parts. microwaves are a lot cheaper to replace then repair, hope this info helps, thanks Bryan
I looked it up in my database, I do service and have access to millions of parts but they say this is no longer available, I checked 5 of my suppliers and no one has it, they all say dicontinued, even if it was available it would run around $172.00 which would make the repaire with service and labor around $300.00, dorry for the bad news, thanks Bryan