It all depends on the model and what is wrong with it.
Give it to a gunsmith
Take it to a gunsmith
Fix and/or repair
Not meant to be repaired by the user.
Not economically feasible.
Without knowing what is broken, we can't tell you how to fix it.
Take it to a qualifed gun smith.
Tattoo guns are not firearms.
Leave it to a trained professional
Take it to a qualified repair shop
u buy another one
Take it to an authorized repair center