A schematic showing a 20 pin DIP inside a 28 pin DIP footprint with various traces run to connect the pins together.
https://files.mastodon.social/media_attachments/files/110/979/876/916/402/350/original/c773c7f5679dbb2c.png
I created this adapter board for a 27C512 EPROM to work in place of a MMI 6309 PROM. I'll think about this some more and maybe order some boards to try it. $5.50 for three at OSH Park, not bad.
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