does the slam tilt happen any time or when a certain target is hit?
could be a switch shorting to ground or a column or row wire shorting to something or a bad ground connection some where.
Is this the double ended soccer ball machine?
if it is and the boards are lying in the bottom of the cab make sure there is no foreign objects on the boards like a bit of metal or something like that (I haven't seen how the boards are mounted in this machine so i may be totally wrong).
The sound problem is more than likely a connector problem, reseat or replace the ribbon cable between the cpu and sound board (again i am not sure of the board configuration so i might be wrong again)
