Okay, that's just neat. The wannabe electronic engineer in me cringes at all those wires connecting the 72-pin edge connector on the NES mobo to the 72-pin slo

Okay, that's just neat. The wannabe electronic engineer in me cringes at all those wires connecting the 72-pin edge connector on the NES mobo to the 72-pin slot connector that receives the cartridge. At the signal speeds involved, any stray inductance and capacitance from such a setup probably doesn't matter. But, IMO, it would still be better to more directly connect the edge connector to the perf board, and then use the perf board itself for a shorter and more consistent wiring scheme. Or better yet, now that you know the spacing, draw up a mask and etch your own board. Such will reduce the likelihood of frustrating intermittent electrical gremlins in the future.