21 Jun
2002
21 Jun
'02
7:10 p.m.
Verify that you can read another 2764 (incase you have reader problems). Can you swap the 2764 for the Masked ROMs & work without changing jumpers/settings/wiring? I see there are a few HX-20 collectors on the net, they may be more informed. Kev
I think I understand what you are saying. I'm sure they are Masked ROMS or at least that would make sense. They are a 4 chip chipset with numbers: EPSON BASIC1R0 M64020AA to M65023AA.
The thing is however, that in identical machines, the other EPROMS are 27C64 so the pinout would seem to have to be the same or the EPROMS would not work right in the other identical machines, would they?