Sounds like the stop motion has slipped, first check that the balance wheel moves when you have the stop motion free as if to wind a bobbin, if it does not then it is a belt problem, if it does move as normal this is what you need to do, undo the screw in the stop motion wheel, unscrew the stop motion wheel all the way off, you will see a three pronged washer, take the washer off and out it on a different way round, put the stop motion wheel back on and tighten up hand tight only, put the screw back in and then check that you can loosen and tighten the stop motion, then test, if it does not work then start again and put the washer in another position, you can even turn the washer upside down but that seems to be the problem.
drivewithken@blueyonder.co.uk, June 2008
