Replace The Mica Plate as Follows : Prepare new mica sheets.
Remove the old mica sheet. Different ways of fixing mica pieces: the removal of the card slot is the simplest. Do not use any tools. Just pull it carefully from the bottom to the top. When the protruding part of the inner cavity is slightly forced to bend the mica piece, and then push it upward to remove it. If the plastic plug is locked, it can be easily removed by prying out the plug with a screwdriver.
Clean the microwave emission window with a paper towel or rag.
Use scissors to cut a new prepared mica sheet compared with the old mica sheet (because the new mica sheets are larger).
Install the cut new mica sheet in the reverse order of removal. If it is fixed with a plug pin, press it firmly into the hole on the microwave emission window.
It is suggested that the texture of mica is brittle, and it is easy to break if it is bent excessively.