IBM PS/1 Model 2121 4MB RAM Upgrade

[twillkickers]

I have been looking out for a 4MB RAM upgrade for my IBM PS/1 model 2121 for a little while now, and I've noticed that I'm not alone on the forum (See below):
http://www.vcfed.org/forum/showthre...S-1-Memory-Module-(2mb-or-4mb)-for-model-2121

Does anyone out there have a schematic for one of these elusive proprietary memory expansion modules? It would be fun to try and have a few made for the folks who want one of these. Hope someone has that information!

 

[xSchlo]

Maybe it is possible to reverse engineer old module if the schematic is unavailable.
I wonder if it will be possible, to reproduce higher capacity module i.e. 8MB

 

[fogman]

Hello, i also wanted a 4 MB memory expansion and couldn't find one. (At least for a reasonable price)
So i designed and built my own one.
You can find the project files here: 4MB Memory Expansion for the IBM PS/1 2121 (https://github.com/realfogman/ps1_ram_expansion)

Greetings.

 

[ajacocks]

Welcome to the forum, @fogman ! Projects like this are a great help to the community.

- Alex