I’m sorry I have no advice for you; I just wanted to say I got a 301A today (mine in better condition but isn’t making stitches) and they look like really cool machines. Like someone said upthread, if you can get it running it would definitely be worth it.
There seem to be a lot of parts for and videos about this model (at least compared to the Kenmore in working on), and the manual is easy to find free online, so that should help.