Not sure if this belongs here or in the "History" forum, but...
I recently came into a pair of UPA-1Cs which came with what are labelled as M-1 (not M-1A) processors. While I've been able to find the manual for the UPA-1C (which, of course, only mentions the M-1A processor) and the manual for the M-1A processor itself, neither the Meyer website nor Google seems to be able to give me any information at all about the M-1 processor (except for one used gear listing for an M-1 which claimed it had been upgraded into an M-1A).
So, does anyone know the difference between the M-1 and the M-1A? Is this theoretical upgrade process worth it/straightforward/something that I can check and see if the previous owner has already done?
(For the record, I'm not planning on doing anything demanding or even particularly important with the UPAs—they were literally free—but if anyone has any information they can share with me about my mythical M-1 processors I'd really appreciate it.)
Thanks!
-Russ