My guess is that is was a test board for Apple. There are some weird mods to the ram timing with a variable cap and to the negative supply that looks like they were experiments to figure out the tolerances of the chips. The board was wave soldered. You can't fake that on an Apple-1 because of what happens to the back of the board by the regulators. I had conversations about this board with Woz and Daniel Kottke who along with Steve Jobs were the only ones who could have had access to the roms and would have known what the board was. The PCB house workers wouldn't have cared or known what to do with it. This is before anyone even knew the name Apple.
Other than a single replacement IC. All the chips and soldered components are correct for something put together before the byte shop order just different parts than the rest of the boards. All the pre NTI boards are very consistent in parts just the edge connectors were installed backwards on some. The NTI varied on the smaller electrolytic caps. There is only one other known but lost to time Apple-1 with the same decoupling caps (they are different than the NTI, though similar). That board was the preproduction board used for the Apple-1 printed Advertisement. That board also used the same RAM chips, which Apple did not use in the end when they shipped the Apple-1, they used the cheaper plastic ones. So lots of evidence this was not something where someone grabbed a PCB for an unknown computer company risking their job and built their own. Cheers, Corey corey cohen uǝɥoɔ ʎǝɹoɔ On Jul 23, 2016, at 8:55 AM, Noel Chiappa <j...@mercury.lcs.mit.edu> wrote: >> From: Corey Cohen > >> It was not someone at the PCB manufacturer. They would not have had >> access to the prom software. > > So, do you have a theory about where this came from? (There is absolutely zero > snark here, this is a serious question. It's quite a puzzle, and an > interesting one.) > > Maybe a collaboration between two people, one at Apple, one at the PCB house? > 'Make two extra boards, and I'll trade you the PROMs for one of them.' Can't > do it with just a person at the PCB house - as you point out, need the ROMs. > But you'd think that if someone at Apple just pulled a board, that would be > noticed (board count wrong). > > Noel
