Hello TJH,
I can take it that the stop motion when tightened does grip the balance wheel, I suspect there is something jammed in the raceway area, take out the bobbin case and drop the gate down and take out the hook, once the hook is out, that is the half moon shape, the machine should turn, if it does then take a needle and run it round the inside where the hook sits and it will pick up any thread that has been flattened and stuck round the edge, if the machine does not move once you have taken the hook out then you have a problem elsewhere and it will be a process of looking at every moving part.
Ken
drivewithken, May 2010
