Hello, and thank you for using this service. I'll be helping you with your problem today.
So most of the time what happens is that the little plastic hook on the back of the door key breaks so the spring has nothing to attach to. You can drill
a hole in the key to attach the spring so that it'll pull the key down again, or you can replace the key, it's completely up to you.
As far as how to get inside the door, you need to remove the "choke" around the inner door. Open the door and locate the plastic seal that goes all the way around the inner door. This is the "choke" and it's clipped in on both the inside and the outside, all the way around the door. You will need to use a small putty knife or a small flat head screw driver and pry under the choke all the way around to unclip it. Once you have the part removed, you should be able to take the key out and see if there is there is something you can do to fix it or if you just need to replace it.
Below is a link to a video that will show you how to take your door apart. The brand is Whirlpool microwave in the video, but the process is the same if you didn't understand what I was describing above.CLICK HERE
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