Model # GLMB209DSB
, this microwave door would not latch when closed so it would not operate. The door on this unit has two spring loaded latches that snap shut when the door is closed actuating the safety interlocks. I separated the door panels and found the latch return spring was no longer attached to it's tab because the tab had cracked and broke off. Since this tab is part of the outer door panel, the whole thing needs to be replaced, but if you want a quick fix, attach the end of the spring to the choke assembly (see photo) and put the door back together. As long as the latches have spring tension they should work. But this door was under warranty, so I replaced the door assembly with a new one. The door closes and stays closed now.
Frigidaire Microwave Door Assembly Part # 5304440849