With 50+ games sold, it’s really only happened to me once. Firepower sound board blew up on the first game. I threw a known working board in it and all was well but I’m certain that the buyer who drive 100+ miles thought I was an idiot. He declined to buy the game without working sound which is fine, I just felt bad about the situation.
Someone looking for a good players FP in Florida ended up buying it so it all wok out in the end.