I have a compact microwave oven.
When you open the door the light doesn't come on.
When you open the door during a cooking spell the counter carries on counting down
When the bleep goes to end the cooking time, opening the door does not stop the bleep
My guess is that the mechanism that detects the door open is defective and that it might be the case that if you put your hand inside it will start cooking!
Can you fix it? Probably not. Ask a specialist or buy a new microwave.
Stay safe...
Good Luck...
June 2017
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