Looking for schematics of QBUS 32KW memory module.

Douglas Taylor dj.taylor4 at comcast.net
Mon Sep 9 10:23:09 CDT 2019

On 9/8/2019 3:22 PM, Mister PDP via cctalk wrote:
> Hello,
> A few weeks ago I ordered a Sigma 400255 for my H11A LSI-11 computer with
> the hopes of getting a 8" floppy hooked up for VCFMW. For the most part,
> all the tests I ran from the ODT seemed to be AOK. The one this I couldn't
> do it boot RT-11 from my TU58 emulator, as it would crash every time. Every
> since I was able to boot RT-11 on my machine it has been unstable and prone
> to crashes, but i chalked that up to the TU58 emulator, and not the machine
> itself. Since I needed to boot from to TU58 in order to INIT and make a
> bootable RT-11 disk for my system, I looked for other causes for the
> crashes. I ran the VKAA XXDP test, which passed fine. I then ZKMA test,
> which lo and behold listed back there were numerous bad addresses all over
> memory. The only memory modules I have are 3 nearly identical 3rd party
> 32KW memory modules. The one that I have in the system right now came with
> it, and is the one with memory errors. The other two are ones I bought on
> eBay that are in rather poor condition and currently do not work at all. I
> was hoping to transfer some of the 4116 chips from my nonfunctional units
> over to my semi-functional unit, but I cannot find schematics for any of
> the boards because they don't have any marking identifying marking on them.
> If anyone knows where I can find schematics for these boards, that would be
> wonderful. I am including a picture of one of these boards below.
> https://i.ibb.co/sQwZw0j/32kwram.jpg
> Thank You, Gavin Tersteeg

I have the Heathkit Memory Expansion Module Model H11-1 manual for the H11.

Has anyone offered you a working DEC MSV11 32k word memory board - so 
you can get thru VCFMW?  They are as common as hens teeth.


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