Thanks for your response. Just to be certain, I just tore it all down and reconfirmed, in case my memory was playing any tricks.
I have a PC-100B with no expansion card. Thanks again for the advice. smp -- Stephen M. Pereira Bedford, NH 03110 KB1SXE > On Apr 12, 2017, at 2:20 PM, Warner Losh <i...@bsdimp.com> wrote: > > On Wed, Apr 12, 2017 at 11:06 AM, Stephen Pereira via cctech > <cct...@classiccmp.org> wrote: >> I’m looking for expansion memory for my DEC Rainbow. >> >> I currently have 128K RAM, and I’d like to have 256K RAM, so I can actually >> use the Lotus 1-2-3 that I recently purchased (without thinking). >> >> Any suggestions? > > So is this a 100A with a 64k expansion card? Or is it the 100B with no card? > > If you have the 100A and a 3-bank expansion card, you should be able > to remove the 64k chips that are on there and replace them with 256k > chips. You should be able to take it to 832k with 27 256kbit DRAM > chips. 41256-120's in DIP 16 if I recall correctly. Need to set the > DIP switches correctly. This is the easiest path forward, if you are > lucky enough to have this configuration, since chips are easy to get, > relatively speaking, and last time I priced them, they were ~0.70 each > so this will set you back ~$20 from JAMECO. You'll want an anti-static > setup to do this, since the BBSs were full of people that had done > this w/o adequate setup blowing up their card / chips. IMHO, if you > are going this route, it's not worth messing with 64k chips since the > price difference is tiny and the win for 3 banks of 256k on the > Rainbow is big. > > If you have a 100B with no expansion card, I can't help... The > expansion card is the hard bit these days... > > Warner
