Microwave will not heat

My microwave will not heat. It sounds normal to begin with then the vent fan kicks on. Any ideas on what the problem might be and if it is economically sound to repair? I have average skills in dealing with these types of things. Thank you!

Hi.

If everything sounds normal and the clock is counting down but there is no heat you have the bad magnetron.

Here are the breakdown diagrams and http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5205053

Thank you. Post the results.

Simon.

What is the part number so I can order it?

Hi.

The magnetron #WB27X10305.

Thank you.

Simon.