It all depends on the model and what is wrong with it.
Give it to a gunsmith
Take it to a gunsmith
Not meant to be repaired by the user.
Not economically feasible.
Fix and/or repair
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.
Take it to a qualified repair shop
Leave it to a trained professional
u buy another one
It doesn't really matter what air system you have on your gun, it should fix the same way. Depending on the marker, you'll have to follow the manuals to dissemble it. The only air problem that could happen would be the CO2 freezing up in the regulator. The only fix is to set the gun down and let it un-freeze.