On Nov 2, 2018, at 1:22 PM, Electronics Plus <sa...@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_Owners_Guide_Aug91.pdf > > <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
