I have a similar project (but a distinct advantage) which is I have a third
party tape punch/reader unit from an ASR-43 (the dot matrix teletype) and
it has basically a bad controller board (8048 based, EPROMs (1702's) read
as 0x00 on my prom programmer). I'm thinking of using something like a
BASIC Stamp II to talk to the punch/reader unit that also seems to be some
sort of oem gizmo.
The bottom line is/was that such things (ie dead units) might be around to
salvage...
--Chuck