Thanks, but like bitsavers they are all older that the one I have. To be honest, I never saw anything Plessey bigger than 128kB in the wild, so I have to wonder what kind of machine this board came from, although it was in a pile of Qbus things that I got the J boards from.
I'm thinking that maybe it was not sold separately, but an OEM build for military etc, and perhaps it is jumpered to get power from memory - but without the manual or tracing the lands I can't really tell. cheers, Nigel On 2021-10-21 7:25 a.m., Steve Malikoff via cctalk wrote: >> On 10/19/2021 12:57 PM, Nigel Johnson Ham via cctech wrote: >>> I am trying to bring up an 11/23 system in a BA23 box, and the only >>> memory i have is an obscure Plessey one. The only identification is the >>> p/n 705920 with dash-100 in white ink. By counting the chips I make it >>> 4MB, but it does not respond. Since it takes the full 22-bit memory >>> space I can't see how any jumpers would change its accessibility. Does >>> anybody have a manual? > FoothillsGeek on VCFed had a number of Plessey memory manuals and had scanned > some, as mentioned here > https://www.vcfed.org/forum/forum/genres/dec/73251-dec-documents-on-manx >
