There is a big difference between repair of an MC and MM cart.
This is because their different construction. An MC cart can be
repaired in principle from all possible defects while this does not
apply for the MM carts. The MM carts with styli with tension wire
can't be repaired. The usual retip by MM carts consist of gluing
an new cantilever/stylus combo on the restant of the old cantilever.
By MC carts a new cantilever/stylus combo can be glued in the
''joint pipe'' on which (joint pipe) also the coils and suspension
( the ''rubber ring'') are fastend. For the MM carts the best
strategy is to try to find the original stylus. This is, alas, not
possible for the MC kinds. So for the MC kinds one need to
learn what the possibilities are and then make the choice.