Control Panel Works But Micro Wont Start

This is a combo over/microwave unit. We were heating some food and about 1 minute into the process the microwave just stopped. The control panel works fine as we can set a time but when we press START we get 3 beeps. Also, the light does not come on when we open the door.

The lower oven works fine.

Where is the fuse for this microwave? Also, as the light does not come on when I open the door and the micro does the same thing (3 beeps when pushing start after setting cook time) I am thinking it may be the door switch? The manual you provide does not have the micro info, just the lower conventional oven info.

Thanks in advance for you help.