It's been just a little while, things have come and gone that have made doing any more on this project not any easier, but I'm back on top of it now and I hope I'm on the home straight.
Mitch, I'm awfully sorry to hear the encoder didn't arrive in such a timely fashion, I hope you either got a refund from them without much trouble or they eventually got it to you and reimbursed you in some way or another.
As for dumping the PROMs, I've taken the time to build a proper 82S147 -> 2716 adapter board (as proper as my skills will allow) and take some new dumps of both 82S147 chips.
They show up just fine in my programmers software and are different from the dumps that I took back in 2017. I have all of the resources to build another pair of 2716 -> 82s147 boards, and am waiting to receive some more 2716 EPROMs as the ones that I tried months back seemed to be corrupted and wouldn't erase (their contents would change with every read I took, even when done seconds apart).
