GE Profile Microwave Dead

A person was microwaving a squash which blew up in a GE Profile oven model PEB2060SM1SS and then it stopped working. Tripped circuit breaker in house I was told. Checked oven and found 20 A fuse blown. All checks passed on Tech Data Sheet except 5. B. With door both open and closed the resistance measures 0.4 ohms across the power cord line and neutral connections but the way they describe the test makes me wonder if the shorting jumpers are not in the right place, etc. For one thing, they describe the relay without saying which one of the three. I am guessing it’s RY2. Is the 20A fuse a slow or fast blow? I thought I would try replacing the fuse if I can get one locally and see what happens.

Why would a squash blowing up cause the 20A fuse to blow? Would it maybe cause one of the door interlock switches to operate and then blow the fuse? I see that the Tech Data Sheet says that when the fuse is blown, that the monitor switch and primary interlock switches must be replaced. That’s poor design if they have to be replaced just because the fuse blows. What are your thoughts? Thanks.