cjc0@berick.uucp (Curtis J. Childers) (06/06/91)
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@berick.uucp