Hello Taiwo,
Are you sure it is the balance wheel jammed and not the drive belt inside the machine jammed, take the end off the machine first of all and check, or release the stop motion as if to wind a bobbin and see if you can turn the balance wheel, if the balance wheel turns then you need to check to make sure you do not have thread jammed in the raceway area.
drivewithken@blueyonder.co.uk, September 2008
