MSV11 Qbus memory for PDP11/03, can someone provide a roadmap please?

From: Andreas Freiherr <Andreas.Freiherr_at_Vishay.com>
Date: Sat May 25 15:52:45 2002

Gunther,

I posted an answer to your question when you asked first time, but maybe
either your setup or mine needed changing for this post to be visible to
you.

Hoping that you can read this, the idea was to check who is providing
refresh: older MOS RAM boards for the Qbus got their refresh from either
the CPU or the terminator, IIRC. Later Qbus boards did refresh on-board,
so maybe you need to disable external refresh.

I just have my infamous LSI-11 Systems Service Manual in front of me,
and there is a "Refresh Configuration Procedure" that starts:

"1 Is this CPU a KD11-H (M7264-YA)?

NO: go to step 6

2 Does the systemn contain an MSV11-B (M7944) memory?

NO: - The CPU should have jumpers W10 and W4 installed.
    - If the system has a REV11-A (M9400-YA) or a REV11-C (M9400-YC),
jumper W2 should be removed.
    - If the system has MSV11-CD (M7955) memories, jumpers W6 and W7
should be installed in the MSV11-CD.
    - If the system has MSV11-DA (M8044-YA), -DB, -DC, or -DD (-YB
through -YD, resp.), there are no refresh configuration requirements for
this module.

3 Does the system contain a DMA device other than the REV11-A (M7900-YA)
or a REV11-C (M9400-YC), such as an RKV11-D (M7969) or DRV11-B (M7950)?
..."

The complete procedure fills 9 (nine) pages in the manual. I might scan
them if you think this might help.

Regards,
Andreas

Gunther Schadow schrieb:
>
> [Now that I finally sorted out the new ways of classiccmp.]
>
> Hi,
>
> in my VAX 11/780 I have the PDP-11/03 alias KC780. And it has
> the following memory board right now:
>
> M7944 MSV11-B Q 4-Kword 16-bit MOS RAM (external refresh)
>
> But, since I'm planning to upgrade to an 11/785 I need additional
> RAM. When it showed up on ePay I purchased a
>
> M8044-DA MSV11-DD Q 32-Kword 16-bit MOS RAM
>
> but the boot program will not load with this. Why would that be?
> From the error I got it appeared as if may be there is just some
> jumpering to do, but I have no clue as to where and what.
>
> Looking at the UNIBUS/Q-bus field guide beginning from M7944
> and then scanning forward to the next MSV11 I find:
>
> M7955-AD MSV11-CD Q 16-Kword 16-bit MOS RAM with on-board refresh
...
Received on Sat May 25 2002 - 15:52:45 BST