how can I fix Jones 942 old electric machine?

As I was sewing suddenly I felt the needle hit something down below, then it broke. I put in another needle, threaded it up, and very gingerly hand operated the wheel so the needle went down in slow motion. Once again, it was fouling against something down below. I removed the spool and case, the ring and hook ring, cleaned them out (not much fluff and thread) and tried again. It is still happening, i.e. the needle hitting something at the bottom. Does something need adjusting, or what can I do, please?