I got three sold-as-seen Model M's back in March, as I reported here: http://deskthority.net/keyboards-f2/mcdonnell-douglas-anyone-know-anything-about-them-t2316.html?hilit=douglas
First, I decided to clean up the working one, missing its external birthday label. It turned out to be a Jan 1988 model, from the internal birthday sticker. It has the yellow wired-up LED PCB, but not the brass-coloured plate. Following the wiki here, that would make it a "1.5" genration model since it fits neither the first or second gen. descriptions.
Anyway, I started with this:
And achieved this:
Internals, for those interested:
Next I opened up the dead captive cable M, born in Scotland in 1994. The PCB header was detached from the PCB, so I soldered it back on. This brought the keyboard back to life. However, the following keys are not registered: 'Pause' 'Num Lock' '/' '*' 'Enter' (the big one) 'R Shift' ' R Ctrl' 'Z' 'X' 'C' 'V' 'M' ',' '.'
I wonder if this combination points to a particular failure mode, such as a broken track on the membrane? I suggest this due to this previous work: http://danson.grafidog.com/2009/02/model-m-repair.html
I also have a SDL cable 1993 blue logo model that I haven't opened yet. Apart from missing a spring at 'L ctrl', the following keys don't register: 'B' ' N' '?' 'Alt Gr' the spacebar and the left, right and down arrows.
Any hints or tips would be most welcome