When I close the door the fuse blow out why is that

That would be a problem with a door switch, door switch mount, or hinge.

See my help file on door switches here:
http://www.microwavecontrol.com/doorsw.txt

Hi. The fact that the fuse blows when the door is closed is quite logical. There are safetyswitches preventing the oven to start with an open door. As to the fuse blowing, There are 3 possibilities: the High voltage trafo is defective, the voltage doubler diode or the capacitor are defective. You must be VERY CAREFULL when working on these parts: the voltages are LETHAL.

Fuse holders sometimes become weak due to heating. If the fuse is not held very tightly by the holder, the fuse will blow because it gets hot, not because the current exceeds the fuse's rating. If this is the case, replacing the fuse holder would be in order. This is not to be confused with the situation where the fuse blows when the door is opened or closed. In that case it's a door switch sequencing issue, or a bad switch.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_29ad5d1dd86564b0

(Fuse is a ceramic fast blow 20A Little Fuse 0314020 or Eton ABC-20) Melting I²t 631
If the Fuse blows when the door is opened. (not even energizing the microwave) The bottom micro switch (monitor micro switch) is normally closed, (open when the door is closed) however if it remains in the closed state when the door is open you will have a short circuit with the Primary Micro switch. The circuit diagram shows that one of the two switches must be open. I was able to test with an ohm meter. With a bad switch the reading was less than an ohm with the door open and 290 ohms with the door closed - Across the plug with a good fuse. With the new micro switch the resistance shouldn't change by much with the door open or closed.

When a fuse continually blows on a microwave is due to one or more of the door switches to be defective,there is a minimum of 3 and as many as 5 door switchs, some of which should be normally opened, while others will be normally closed. That is built in redundency to assure that the door is closed when the m/w is on since i believe you do not want to be subject to radiation if the m/w could be run with the door open

When a fuse continually blows on a microwave is due to one or more of the door switches to be defective,there is a minimum of 3 and as many as 5 door switchs, some of which should be normally opened, while others will be normally closed. That is built in redundency to assure that the door is closed when the m/w is on since i believe you do not want to be subject to radatation if the m/w could be run with the door open

I assume there is no display at all. First make sure there is power to the microwave. Next would be the fuse INSIDE the control section. It needs a 15 Amp slow blow fuse. If that is the problem and you replace it (first disconnect oven!) and the oven works Ok that sould have taken car of your problem. However to do a little test you could, after having replaced the fuse, open and close the door several times. If it blows the fuse again that means that there is a problem with the door switch sequence. I don't know if you want to go this far, but there is one "normally closed" switch that, when closing the door, needs to open before the "normally open" switches make contact. Conversely when opening the door the "NO" switches need to open before the "NC" switch makes.

you will probably find that the fuse blowing is due to door switch adjustments, most unit have 3 switches 2 on the door catches and one that is crowbar protection. the 2 door catch switches are normally closed with the door open and the crowbar is the opposite. if they do not change at the correct time when closing nthe door the fuse blows

first you gotta detach the button plate ( the thing with all the buttons) using a flathead screwdriver .Keep pushing it is stuburn. It will pop back in when you are done. the fuse is behind that. just take it out and put the new one in.

The door latch switches, and monitor switch assembly needs adjusting. With the door open the two latch switches should be normally open,and the monitor switch closed. Opposite way when door is closed. MAKE sure oven is unplugged before testing