Thanks bb, that is helpful.

I have been able to read the two ROM chips into hex files, by identifying them as 27C512s.

Can I use those dumps to verify against a dump from a known good ROM set?

Are standard ROM dumps available for comparison and/or burning to EPROM?

I know so little about the particular machine at the moment, I am still wondering whether some other hardware issue might be stopping the ROM read, such as caps or address-handling chips.

Rick