The Motor control Board is faulty. Also you have to check the carbon brush of the Motor .
If you wish to get some details; check the site linked here. Pull up older posts.
http://electro-medical.blogspot.com/
A sudden load can be enough to cause the fuse to blow rather than a short. Replace the fuse either with a 250v 10A Slow blw fuse or us a 250v 15A standard fuse. If it still blows then there is a definite fault. Motor Loading from lack of Lubrication etc.
Or a wiring short. Fuses are available from many suppliers. The shape of the fuse being used and how it clips into the board will be import and. Take a sample or an iPhone photo with you.