Hello:
Have to admit that the only vintage machine we have is a Featherweight that was in wonderful condition when found 3 years ago.
Yesterday we did get the machine to zig zag and do a blind hem stitch. None of the other stitches. In one case the special stitch dial was in a position other than the stitch done, so it may be that dial is not working properly and not switching to other stitches.
We do have two bicycle shops and a nearby neighbor has 5 bicycles so will check with them.
Thank you for the suggestions.