I have a 638 T&S......first thing is to make sure the buttonhole controls are in the off position. Is the pressure foot raised for bobbin winding? You say you cannot push the bobbin button to the left......does it move at all? Is there lint or thread blocking the button action......the slide plate must be open as much as possible without removing it from the machine. When I wind the bobbin on mine, I hear a distint click/snap sound. Did you get a manual as it has information that will perhaps help you more than I can? Make sure the bobbin area is clear of lint and threads.....the presser foot must be raised and the needle in the highest position. On my machine the needle position must be at C (Center) and the stitch width at 1. Hope this helps you somewhat. Budster.