WTB: DEC Rainbow Expansion Memory

[Warner Losh]

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
>
>
>