Hi, welcome to Just Answer. My name is XXXXX XXXXX I look forward to helping you! The button should unlock the pressing plate when depressed, not a lever. That button is number 10 in the top picture. Does that button feel different than it has in the past, like it may be broken?
Thanks; that button did work,, although not as easily as it should. There is a lever under the board that has to be pressed along with the button on top, however. At least that is what worked for me.