21 Oct
2021
21 Oct
'21
6:10 a.m.
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