Panasonic HHC ROM 'capules'

[brouhaha]

(01-16-2023 04:13 AM)Paul Berger (Canada) Wrote:  and the EPROM that are in it are Intel 27128A which are the 250nS NMOS part.

It does seem like NMOS EPROMs (2732[A], 68764/68766, 27128[A]) are more likely to work satisfactorily than newer CMOS parts, in part because the NMOS parts have somewhat different ESD protection characteristics, and don't power the entire chip fram any I/O pin, like the clamp diodes in the CMOS parts.