Did this ever get sorted? I have the identical issue (though mine seems to never go away) on an NBA Fastbreak. I have not fully rebuilt the driver section for the particular coil outside of replacing a few TIP102s that keep failing as none of the other parts appear bad. What I did do was swap parts around on the driver board to see if the problem followed and it did not. The LS374 seems fine as well since no problems show up in diode test or with a logic probe. The fuse associated with this coil (in NBA's case, the shoot coils are driven by the unused flipper transistors and it's one of these that's failing) will blow sometimes and not other times. The TIP102 will blow almost immediately during a game but will not fry if I don't allow the coil to stay held during switch test. Coil was also replaced/tested just to make sure but it's fine as well. So I'm stumped.