WTB: DEC Rainbow Expansion Memory

On Apr 12, 2017, at 3:49 PM, Warner Losh <imp at bsdimp.com> wrote: Thanks! I have another experiment to try, but need some parts for that, so it will have to wait until they arrive. the unit has been a bit flakey this time, so I don't know if I need a new controller board, new RX-50 or a new power supply. Or a ROM refresh.... Warner On Wed, Apr 12, 2017 at 1:47 PM, Stephen Pereira <spereira1952 at comcast.net> wrote: > Wow. Since misery loves company, I guess we make a great pair today! > > Good luck with your equipment! > > smp > -- > Stephen M. Pereira > Bedford, NH 03110 > KB1SXE > > On Apr 12, 2017, at 3:41 PM, Warner Losh <imp at bsdimp.com> wrote: > > For you and me both. I was getting read errors on my RX-50, so I tried > to swap in a new drive, and now that's all I get as well. Guess I'll > have to figure out another way to get the Venix/86R disks copied. > > Warner > > On Wed, Apr 12, 2017 at 1:23 PM, Stephen Pereira > <spereira1952 at comcast.net> wrote: > > I guess it doesn?t make any difference now. I reassembled the computer and > now I get a message 28 ?RX50 Controller Board" failure during POST. > I?ve taken it apart and put it back together several times, but I cannot > clear the failure. This really has been a bad day! > > smp > -- > Stephen M. Pereira > Bedford, NH 03110 > KB1SXE > > On Apr 12, 2017, at 3:07 PM, Warner Losh <imp at bsdimp.com> wrote: > > On Wed, Apr 12, 2017 at 1:00 PM, Stephen Pereira > <spereira1952 at comcast.net> wrote: > > 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. > > > Bummer. The cards come up from time to time in different places, but > there's none on ebay right now. Last summer there were like 5, > including one that had an 8087 coprocessor option... > > smp > -- > Stephen M. Pereira > Bedford, NH 03110 > KB1SXE > > 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: > > 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 > > > >