After doing some research the problem appeared to be the door safety switches. I ordered 3 new ones to replace all the original ones. Some minor disassembly of the microwave front was required to reach the fuse and switches. To reach the switches the control panel wires needed to be unplugged and the panel removed. After doing that replacing the switches was pretty strait forward. As of this comment the microwave has worked for 5 days without blowing the fuse so far. This has probably fixed the issue.