Kitchenaid Superba oven/micro combo KEMS377 - died - please help

We bought a used Superba oven/microwave combo a few weeks ago. Just installed it a few days ago, which seemed to work fine.

Been doing some reading, and found that these Kitchenaid units are nothing but problems. Sounds like it is either the internal thermal or line fuse.

Does anymore have a tech sheet showing me where these are located. Anyone know the model/type of fuse that I need? Is it unusual for the fuse to blow when using both oven and microwave at same time?? FYI - heard it is very common when doing the self cleaning mode, so maybe using both units is bad too on these??

Thanks