• Please review our updated Terms and Rules here

Rainbow 100A Memory beyond 256K?

if you are interested I have 4 RAMbow pcb of the prototype that I can send.
the bcb is wrong but recoverable with a modification on the flat cable.
in case send me a P.M.
 
Lol once again VCFed forums fails to notify me of additions to this conversation! I'm happy to get a set of these finalized pcbs run off (so I will end up with a couple spares if anyone wants) and just build the whole project from na103's (excellent!) github directions. I've ordered a set (with extras) of the 1mbit chips from UTSource, and I'll fling more money at Digikey for the rest :)

This is all very exciting. Brilliant work, and I bet you the Ebay price of 100As just doubled :)
 
Board finally arrived! I will get to building in the next day or two. na103, do you have any recommendations as to how to test my construction work before I connect the card (e.g., some pin-to-pin sane resistance levels, etc?) I would prefer to avoid generating the magic smoke from a goof on my part (I have exactly one 100A lol)

Cheers! A
 
alitel said:
Board finally arrived! I will get to building in the next day or two. na103, do you have any recommendations as to how to test my construction work before I connect the card (e.g., some pin-to-pin sane resistance levels, etc?) I would prefer to avoid generating the magic smoke from a goof on my part (I have exactly one 100A lol)

Cheers! A
Click to expand...
check the IDC cable of the J2 socket carefully. insert the board on you rainbow and check that there is no short circuit between 5V and GND.
then cross your fingers and turn on😄
 
na103 said:
if you are interested I have 4 RAMbow pcb of the prototype that I can send.
the bcb is wrong but recoverable with a modification on the flat cable.
in case send me a P.M.
Click to expand...
Do you have any more boards? I dont mind If I need to make a change due to error. I only need one board.
 
Hi all -- I want to report initial success! Wooo, got it built and it SEEMS to have worked first go (touch wood and all that)! BRILLIANT work by na103!
 

Attachments

  • IMG_20240703_143834_099.jpg
    IMG_20240703_143834_099.jpg
    5.8 MB · Views: 13
alitel said:
Hi all -- I want to report initial success! Wooo, got it built and it SEEMS to have worked first go (touch wood and all that)! BRILLIANT work by na103!
Click to expand...
Do you happen to have a spare board to sell?
 
VERAULT said:
@alitel Do you have a board to spare?
Click to expand...
Hi Verault, I have two spare boards at this point (ordered, 5, used one, one bespoke and keeping one for future), so you're welcome to one! They cost me about $10 USD per board to get made, so happy to send to you for that plush shipping costs? (whichi will of course be more than the board lol). Let me know what you'd like to do -- If you want to pm me with address etc I can look into shipping it.
 
alitel said:
Hi Verault, I have two spare boards at this point (ordered, 5, used one, one bespoke and keeping one for future), so you're welcome to one! They cost me about $10 USD per board to get made, so happy to send to you for that plush shipping costs? (whichi will of course be more than the board lol). Let me know what you'd like to do -- If you want to pm me with address etc I can look into shipping it.
Click to expand...
Sounds good to me. I will PM you. Thank you!
 
I forgot -- the only item I ran into on the build was that on my pcbs (and I haven't checked the gerbers yet to see if it was a fab error), there was no 4th corner hole drilled in the pcb to slot into the plastic standoff on the motherboard, so I have one corner of the card less well supported than usual, but it's completely fine (I just pulled the standoff out for now). Just an FYI.
 
alitel said:
I forgot -- the only item I ran into on the build was that on my pcbs (and I haven't checked the gerbers yet to see if it was a fab error), there was no 4th corner hole drilled in the pcb to slot into the plastic standoff on the motherboard, so I have one corner of the card less well supported than usual, but it's completely fine (I just pulled the standoff out for now). Just an FYI.
Click to expand...
is there room to drill that sport or are traces in the way?
 
Looking at the kicad pcb layout, I suspect na103 left it out deliberately as there are some traces pretty near that corner? I'd be careful drilling :) Perhaps the traces can be tweaked on the next version, but honestly, not a huge issue IMO :)
 
alitel said:
Looking at the kicad pcb layout, I suspect na103 left it out deliberately as there are some traces pretty near that corner? I'd be careful drilling :) Perhaps the traces can be tweaked on the next version, but honestly, not a huge issue IMO :)
Click to expand...
yes I didn't make the hole for the support because it seems to me easier to remove and insert the board and I also gained space for the traces.
 
Hi all -- this is not directly related, but since we were all interested in the guts of the Rainbow's operation in this thread -- I found an interesting file named RBTECDOC.ZIP here:


It's full of pretty neat documents from the era -- especially interesting to me is the EMULAT84.TXT file in the archive which talks about software called Emulate-84 by Operating Scientist, Inc. Basically an MS-DOS compatibility program a-la Code Blue. If anyone's ever heard of it (or has a copy!), I would love to obtain.

There's also a mention of the elusive PC1K1-AK memory adapter board for the 100A, allowing > 256k, in the file RBMEMRY.TXT in this archive.

Just thought it was cool, and was not sure if people had seen all these files, so figured I'd share.

Cheers!! Alison
 
You must log in or register to reply here.
Back
Top