21MX proms (per request

Marc Verdiell marc.verdiell at gmail.com
Tue Sep 8 14:14:00 CDT 2015

>From: dwight <dkelvey at hotmail.com>
>If I were doing it.
>First you need to find out if it needs OC output.
>There are many flash parts in surface mount that can have the higher
>Add some 74LVC245 to give bus drive needed, also surface mount.
>All on a little PC board. There would be a lot of wasted space in the flash
but what the heck.
>Put an edge connector on the board to deal with programming.
>All will fit in a smaller space than the original part.

That would be great engineering fun! But at less than $4 for the blanks,
using the old PROMs and the vintage programmer seems pretty straightforward,
vintage correct, and low risk solution. Miraculously, my best offer got
accepted on ebay, so semi-affordable vintage clunky Data I/O 29B Programmer
and plenty of blanks are being shipped to me :-). I count collecting vintage
tools for servicing your vintage machine as part of the fun too...

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