I took a 401 in trade the other day. Today I tackled it. I knew the stitch selector was frozen. I cleaned and oiled. As I cleaned and oiled I realized it was much worse than I thought it was - the zig zag pins were frozen - the front and back selectors were frozen - the needle arm was not moving at all either. I oiled, gave time out, oiled, took apart things I didn't want apart - oiled, cleaned put things back, still frozen. I took time out. I finally used heat. I hate using heat. After 4 or 5 hours... Now it just needs the tension worked on - I noticed the screw that holds the bobbin tension is very loose. I bet the upper tension has been tampered with, too. The pressure foot tension was all but off - one more turn and I think someone might have been in for a surprise. That will need some adjustment, too.