Thank you for your question.
I can understand wanting to know what to do in getting the sewing machine running again.
It sounds like it needs a good clean and oiling.
First remove the needle plate and clean the spaces between the feed dogs.
Then remove the bobbin case and shuttle hook from the shuttle race and clean the lint from this area.
Examine the back side off the shuttle and clean the half gear and the shuttle gear as best you can.
Then open the upper left side cover and clean and lubricate the take up lever and the needle bar and any moving parts you can see at this end. You may discover some thread rapped around the take up levers, if you do please remove this thread.
If you can turn the machine over by the hand wheel it will help the sewing machine oil getting into those moving parts.
Because this machine has the clam shell designed covers, (front and back) it will be difficult for you to lube the top main shaft area.
If, the suggestions of cleaning and oiling the machine does not help, then I would suggest you take the machine in for servicing.
If you feel comfortable with removing the covers your self to get to the interior of the machine please let me know and I will be happy to help you.
Removing the covers can be a little tricky, so some will decide to take the machine in for service.
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