rhaar@albert.cs.gmr.com (Robert L. Haar CS50) (02/15/91)
In article <1991Feb15.030125.20383@ra.src.umd.edu>, zafar@eng.umd.edu (Sohail Zafar) writes: |> I successfully upgraded the ram card to 2.0M and want to do the same for the |> motherboard. BUT I don't have anymore patience left to pull out another 72 ICs. |> What I want to do is cut the 64K chips with a cutter and use 1M RAMS by making |> a small board and using jumpers from the motherboard to this daughterboard. |> I will thus have to desolder only a fraction of the pins! What I don't have |> is the hardware manual (to be specific the scematic and circuit diagram). I am |> planning to use two 1Mx8 and two 1Mx1 chips, so I will have only four chips for |> 2.0M of memory. I want the circuit diagram for the decoder chips. I would |> appreciate if someone who has the hardware manual could send me a copy of the |> circuit diagram or lend me his copy of Hardware manual if living in the |> Washington Metro area. I tried to e-mail a response, but it went to hellcat.eng.umd.edu, which said that there was no such user as zafar@eng.umd.edu. I think you have a hard task - not only intercepting the address decoding and inserting you own circuits, but also the physical constraint of fitting a daughter board in the vertical space between the motherboard and the metal cover plate. I have the hardware manual and will copy the memory section for you. It will be next week before I get to it. BTW - your address is very familiar. I lived at 4331 Rowalt while attend UofMd - Ph.D. in C.S. 1980. Bob Haar InterNet : rhaar@albert.cs.gmr.com Computer Science Dept., G.M. Research Laboratories DISCLAIMER: Unless indicated otherwise, everything in this note is personal opinion, not an official statement of General Motors Corp.