I'm trying to open my wife's 1471. The presser foot mechanisn has lost its downward pressure and I would like to do some troubleshooting before I resort to a repair shop. I can only find 2 small Phillips drive screws to remove and those don't seem to do much as far as taking off the top. I had hoped to find an exploded view of the machine with some ideas as to how to disassemble it. Any help will be appreciated. Jim