Wanted: another 12C for reverse-engineering (two-chip, non-diaper)

[brouhaha]

I'm looking for another 12C to purchase for reverse-engineering to support making Nonpareil's Voyager hardware simulation more accurate. Mark Shin was recently kind enough to gave me a 3210B serial prefix unit for that purpose. That's one of the SST units (described in Chuck McCord's presentations at the 2022 HHC and HPCC conferences), and although I'll attempt to find the test mode that allows access to the bus, I'm not there yet.

In the mean time, I'd like to get a two-chip 12C, but the single-rigid-PCB model rather than the original version with the polyimide flex circuit for the chips and LCD. The early version had the electronics wrapped in a black plastic sandwich ESD shield, sometimes called the black diaper. While that version is electrically fine for what I need to do, it's much harder to solder wires to the appropriate signals, and I'm not sure that I can cut the ISA line between the Nut and the R2D2, which I plan to do to inject instructions. (A microcontroller will control a 74HC4066 transmission gate to disconnect the ISA line when injecting instructions at addresses the R2D2 would respond to.)

I think the single-rigid-PCB non-SST model was made from 1982 through at least 1988.

I need a unit where the keyboard works fairly reliably. I bought one in the right serial range on eBay, but the keyboard is very unreliable, which appears to be at least in part due to many of the heat stakes popping off the board. In general it's hard to find what I'm looking for on eBay because most 12C sales on eBay are either the much newer versions using one or two CR2032 coin cells, or the photos don't clearly show the serial number.

Aside from the keyboard and display working correctly, and passing the self tests, it's OK if the unit is somewhat beat up. I don't want to spend a fortune to buy a pristine unit.

So if you have such a unit you'd be willing to sell me, please DM me with your asking price.

(Other Voyagers models of that same construction would be welcome, but those are rare and valuable, so quite possibly out of my price range.)

Thanks!
Eric S.