I use a 500A as one of my 'line' machines for garment sewing - ZZ and decorative stitching as well as button sewing. Very reliable, I do not understand the problem you are having with the needle bar. I cleaned mine with kerosene, sewing machine oil, and lots of q-tips; and maintain it with sewing machine oil. Really work at cleaning a newly acquired machine and it should do well for you. Good luck!