depends where break, but better buy new one. no point fixing. even if can be able to fix, head balance not same anymore.
I repaired my broken AT900P at shanghai,and they did it so well.Best i've seen in china's market.Added less than 1 g but able to hold up to 25-26.
If it is a cheap racket then just buy another one since it would probably cost just as much repairing it.