Jay -

Recc. you chuck it; 14 years is an adequate life for a microwave. If
you want to keep it, I advise you take it to a service center for
repair.... given the cost of new, it wouldn't make financial sense to
repair it, however unless you are familiar with the operation of high
voltage power supplies, and how to deal with them, playing around with
the guts and/or replacing parts would not be a wise idea.