Are slapstic chips interchangeable?
Sadly, no. They were designed to prevent operators from burning new EPROMs and “upgrading” their PCBs to a new game without buying the necessary kits from Atari. For example, the five System 1 games each used a different slapstic, so that you couldn’t take, say, a Marble Madness machine, burn new EPROMs, and convert it into an Indiana Jones. That said, however, there are two pairs of the slapstics that appear to be functionally identical, despite the fact that they have different part numbers: 137412-103 (Marble Madness) appears to be functionally identical to 137412-110 (Road Blasters & APB) 137412-106 (Gauntlet II) appears to be functionally identical to 137412-109 (Championship Sprint & Road Blasters) Note, however, that I have not tried these swaps to confirm that they work. Your mileage may vary.