Looking for schematics of QBUS 32KW memory module.

Mister PDP vintagecomputersmn at gmail.com
Sun Sep 8 14:22:41 CDT 2019


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.


Thank You, Gavin Tersteeg

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