Simplicity Model SL 415 Sewing Machine Not StitchingI have a Simplicity model SL415 sewing machine. I have had it for maybe 25 years and never had problems. Last week I was sewing and the stitches would skip and maybe do a stretch stitch. Today I started and it won't pick up the thread to make a stitch. I've cleaned it, oiled it, and changed the tension, but it will not stitch.