if your control box is like the one in this post :-
http://www.cnczone.com/forums/chines...oc-pw3024.html
you will see from the circuit diagram in the post there is two fuses
one for the stepper driver DC supply & one for the speed control
if your very lucky you may of blown fuse F2 that powers the spindle motor
check resistors R 3 & R4 have not been burnt by the overload
John