WTB: DEC Rainbow Expansion Memory

On Apr 12, 2017, at 2:20 PM, Warner Losh <imp at bsdimp.com> wrote: On Wed, Apr 12, 2017 at 11:06 AM, Stephen Pereira via cctech <cctech at classiccmp.org> wrote: 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