Radiation hazard?

My GE microwave (model JES145DNWW) stopped heating. Everything else seems to work. I pulled the cover and found a melted connector that is plugged into the circuit board where the main power cord hooks up to. I cut the wires from the melted connector and put new stacon terminal on them. It still didn’t work. There is a in depth trouble shooting guide inside the microwave but I’m not too sure about the hazards of working on it with the cover off. Is this a problem? And also if you could give me some idea what to check out it would greatly help me, since some of the symbols on the diagram are not too clear. I am an electrician, so I am familiar with how to use a meter, ohm for continuity, and read schemactics fairly good. Thanks for any help you can give me.