not extra loud, but an unusual "rattling" sound.
Okay, your problem is the magnetron. This is the device that makes the microwaves to heat the food. What you need to do is to replace the magnetron and when you replace that you should also replace the high voltage diode since it can make the magnetron go bad. I am sending you a link to a diagram of your microwave and the magnetron is #61 on the diagram and the diode is #77 on the diagram. I am here for further assistance and thank you for your time and patience, Randy.
Sorry about the delay and if you are a good handyman, you can do it yourself. The first thing you will have to do is to take the microwave down from the wall. Let me know if you are up to it.