If you take off the blue top lid I think you can access the bobbin tyre and the spring mechanism under there. It might need replacing if it's hardened or comming appart. I assume it runs on the back of the hand wheel. You should be able to do it with out the repair manual, but it's always a pluss to have it when you need to go through a machine thoroughly. There is the Elna Yahoo group, it might be available there.