On Nov 2, 2018, at 1:22 PM, Electronics Plus <sales at elecplus.com> wrote:
Memory
User-installable RAM boards provide the 425 with RAM in increments of 8, 16
From
http://bitsavers.trailing-edge.com/pdf/hp/9000_400/A2100-90600_HP_9000_425_…
<http://bitsavers.trailing-edge.com/pdf/hp/9000_400/A2100-90600_HP_9000_425_Owners_Guide_Aug91.pdf>
Yes, I?ve read that, thanks. What I need is the actual *pinout* for the memory boards
which is the sort of thing that?d be in a hardware reference manual rather than a user?s
manual. (Along with pinouts for the DIO-II expansion slot.)
If this is standard ECC memory, then I have plenty of
it on hand. But HP was known to use some really funky looking memory.
They use standard *memory* on non-standard *boards*.
The ICs are standard, for example in <https://www.hpmuseum.net/display_item.php?hw=863
<https://www.hpmuseum.net/display_item.php?hw=863>> a 4MB board uses nine 80ns
514256 ICs and a trio of 74AS1004 hex inverter-drivers. However, the boards are not SIMMs,
they use a 72-pin header.
My theory is that given they used the same ICs as everyone else, it should be easy to
design and fabricate a SIMM adapter from the board pinout.
This RAM also appears to have been used in the HP-9000/375 and /380, in case someone has a
hardware reference manual for those.
-- Chris