qbus module ID

[Eric Smith]

Pete wrote:
>    I have here a M8637 memory module, no additional info on the board to
>    identify which variant, I would be expecting CA or EA, as down one
>    side is printed "QBUS 2MB MOS MEMORY".
>    Any hints on how to work out which it is?

If it's half-populated, it's a -Bx or -Dx.  If it's fully populated,
it's a -Cx or -Ex.  The second letter of the suffix varies depending on
the manufacturer of the RAM chips.  The first character of the module
suffix is the same as the second character of the MSV11-Jx option part
number.

Unfortunately I don't know how to tell the -Bx/-Cx modules, which are
for use only in the PDP-11/84, from the -Dx/-Ex modules, which can be
used in the 11/84 or in QBUS/PMI systems.  The information needed to
determine this is probably in the EK-MSV1J-UG user's guide or the
MP02056 maintenance print set, but I don't have either.

Eric