If you get the sounds means the driver board is good registering the score. Agreed, fuse is known to blow alot if the upkicker mod is not performed. The original relay would burn and cause problems Be sure to add a 4.7mf cap between pins 5 and 6 of the PBDB otherwise flipper activity will make it pop incessantly. The cap cuts down on noise. The transistor that controls the kicker is on the PBDB, make sure the coil and the PBDB is receiving power first and go from there.