< 34 and 20...sounds kinda like an MFM disk interface, or perhaps ESDI? < <>There is a NEC D7261AD chip on the top, an uncovered EPROM (worrisome), <>several PALs and a large chip (68pin DIP) labelled AM29x305 Nope of EDSI. The 7261 is a MFM controller chip. < Just thinking aloud here, but that AMD chip sounds like a second-sourced <8X305 by its number and physical description. I didn't know they did anyth <from that family. Those are neat processors...and pretty much the predeces <of today's PIC family. Neat! Maybe, The 8X300 is before that. Nothing like PIC though. None of my AMD books have that part and the vintage is '82 to 85ish as that was the window for the 7261. Allison < < -Dave McGuire <