> Someone should explain how Fujitsu chips are a bad sign in Mame? This looks like to > me these chips are very well designed. It's no surprise Sega used these chips on > their comm boards before Sega Model 3.
The problem with Fujitsu is that documentation tends to be quite difficult to find regarding their more obscure ICs, and they made a lot of semi-custom products for various arcade manufacturers (which go all the way back to the MB14241 barrel shifter on the black-and-white Midway/Taito games) for which little to no official documentation has ever been published. It's part of the reason why Sega Model 1/2 emulation has been such a difficult struggle.
(PCB maintainers also curse the failure rate of Fujitsu TTL chips, but that's a different subject entirely.)