need assistance on memory upgrade/hardware changes

Curtis J. Childers cjc0 at berick.uucp
Fri Jun 7 01:44:04 AEST 1991

I have a unixpc, 20mb w/1meg of system memory.  I've decided to upgrade it,
but I've run into a couple of problems.  AT&T has made quite a few patches
to the motherboard, and I'm confused as to which patches to undo to make the 
motherboard recognize a second meg of memory.  I also wish to buy a larger
harddisk, but ST4096 (80mb) drives seem to be getting rare.  Besides, I'd 
rather have a larger drive anyway.  I've heard that someone has plans or a kit
to allow drives of greater than 64 meg to be fully utilized.

Let me go into detail on what I've done to my motherboard to attempt a
memory upgrade.  I installed 40 16-pin sockets, 36 for memory & 4 for 74F258
chips.  I installed 4 330-ohm resistor packs (non-common), 15 104-caps,
12 103-caps.  When I plugged the memory and support chips in, I could see 
activity on the new memories address and data lines.  However, the CAS was 
always inactive.  I traced this problem to the patch from IC 6J pin 3 to
IC 6K pin 1.  I restored the original path from IC 25E pin 15 to 6J pin 3.
However, this didn't fix the problem, so I undid the patch from 22E pin 17
to 22E pin 20, reconnected pin 17 to R108, and undid the patch from 20E pin 4
to pin 5, and connected pin 4 to the otherside on r108.  I still didn't work
so I undid the patch from 24K pin 1 and pin 13 to 17K pin 12 and reconnected
them to 17K pin 9.  When it still didn't recognise the memory I figured I
was over my head, and any other changes would just be shots in the dark.

If anyone can help me, please send me E-mail at: cjc0 at berick.uucp

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