[HayZee518]

check the connection [which you say is unlikely] check the door switch(s) there may be two of them which interlock when the door is closed. the magnetron uses push on spade connections check these out. never operate the unit without some sort of sheild around it. spurious radiation could be harmful. the magnetron operates around 27-28 mHz same as a cb radio. check to make sure the waveguide is securely fastened to the "cavity" your oven. If there is an interrupter paddle make sure the motor is distributing the microwaves.