Hello Watheen, I saw you did post in the vintage section, I'm sure someone there will start asking the questions they need to know to find your answer. For quite awhile I used to pick up old machines, not so much fix them as clean them and get them operational and then they went to a charity that connected them with recent immigrant households or other people who wanted sewing machines so I have some basics in repair and cleaning but not the knowledge you need.
For most of the last 30 years I've been sewing on a Remington, a metal vintage Japanese machine much like a Morse. It is older than me and belonged to a friend's grandmother. It has a wonderful sturdy consistent straight stitch. A little over a year ago I was given a new-to-me modern Bernina that needs to go to the shop, so I'm back to my backup machines.