There are magnetic ballast repair kits that are about $60, just swap out your bad parts for the good parts, or if you know exactly what is blown, you can just order that part from a electronics supplier and swap it out. There isn't much that can go bad in a ballast, you've got your supply, a few capacitors, and not much else, did they pop or fizzle? usually this is a capacitor, sometimes also followed by a puff of smoke, now and then you can get alot of smoke from the power plant going out, and some of the power plants will have a small inline fuse attached to them, check that fuse too. (Sometimes these fuses are on the side of the ballast where you can unscrew it and pull them out)