larwe ha scritto:
It would also require using old stock chips, because anything newer might very likely have had a die shrink and be easily identifiable (even by the naked eye) as modern. EPROMs are the obvious candidate there.
agree on all points, but save the chip markings: I think that looking the die size under the hood of an (allegedly) genuine and *working* machine means also destroying the chip, and replacing it reduces the value of the machine, if really genuine....
I doubt that one opens or x-ray an, let's say, 7720 6502 CPU to see if is actually a 7720 and not, say, a 88xx 6502.....
Deleting the prod number and writing an earlier, fake prod number (and same treatment to the other anachronistic markings on the chip) is relatively easy, I fear...
Best regards from Italy, Dott. Piergiorgio.