I would start by double checking the threading, even tripple check. Track down a pdf manual on the web if you don't have it. I would then check the needle position, if it's in the correct way. Your model probably allows the needle to go in one way only, but I just mentioned it because "flat side to the left, right or towards the back" is a common mistake to make with many vintage machines. Make sure you thread the needle the correct way, make sure the bobbin area is clean and lint free as well. Bobbin needs to go in the correct way. I have had the needle off position enough to cause problems, nothing was reall yworng, but a lot of lint build up behind the needle clamp where the needle goes in sort of pushed the needle off to the side. The groove needed to be scraped clean with a tooth pick.
It might sound tedious, but even hardly used machine can use a bit of extra effort when it comes to oiling and lubrication; repeated applications, turning knobs, levers and test sewing is the way about it. Poke the swing arm ligthly with your finger to make sure it moves freely and all the way left to right. Do a bit of inspecting every where when you clean and oil; poke moving parts to make sure things move as freely as they should. I'm sure basic maintanance and a bit of trouble shooting will get to the problem.
Last edited by Mickey2; 10-29-2020 at 02:14 PM.