IBM has tweaked their Model M design over the years, I thought it would be a good idea to make a thread to document this.
I noticed several differences while working on an M to F conversion kit. Check out the interest check (
I would love to see what Model M parts you have, please share in the comments and post pics if you can. Lexmarks/Unicomps etc are all welcome!
I will start. I have 3 variants:
SDL controller sits on the back

Membrane is glued to the rainbow back plate

The spacebar stabilizer guides are glued to the top so there are no holes like in later models; it also has these on both of the 2u numpad keys

Controller with non-removable cable screws into the back plate like this

but the bottom case still has the mounting tabs for the SDL controller!

Stabilizer guides for the spacebar are now built into the barrel plate - this presumably makes them harder to break but it creates holes in the barrel plate (due to the manufacturing process)!

The mounting tabs for the SDL controller are gone

Channels for guiding spills through the board, but it seems a bit pointless when there are still holes for the spacebar
