Take apart every place you can get a screw out or pop a cover off, including the bottom cover and clean and oil everything. Put it back together and enjoy your stitching. I was given a 533 on its way to the dumpster. My granddaughter cleaned it with Simple Green and and a toothbrush, then did the cleaning and oiling. She now has a very nice stitching machine. Something is wrong with the zigzag, but for quilting, it sews well.