bstone@convex.com (Barry Stone) (11/01/90)
I have acquired a Compaq Portable. It came with 256K of RAM; 18 64K chips that are soldered onto the motherboard and 18 64K chips in sockets. Can I upgrade to 640K by replacing the socketed chips with 256K chips? Do I need to change switch settings?
dchou@NCoast.ORG (David Chou) (11/01/90)
Boy does this bring back memories. I did this on one of my Compaq portables but it wasn't easy, even though it should have been. I got a bunch of 256k chips (I think that they were 250ns and expected that replacing the socketed chips would bring it up to the required memory - like alot of systems which size memory on startup. It turned out that I needed a small 16pin PAL for fixing up the address lines on the chip. If I were a little smarter at that time, I could have even made the PAL myself. As it turned out, I tried to get this part from the local Compaq dealer, and this turned out to be totally futile. I ended up getting a replacement BIOS chip which I did not need, but it only cost me $25. Well anyway, I then tried to contact Compaq to get the proper part number, but Compaq refused to even talk to me unless I was a dealer or an OEM. I finally worked through an OEM I knew in Houston who somehow got the part to me some time later. It is basically not hard to do, but to get the part number for the replacement PAL is impossible for the average user. The part is fairly inexpensive, but since I never talked to Compaq, I never did get the part number. Good luck. Dave Chou ncoast!dchou@cwjcc.cwru.edu .