Keyboard Key (Capacitive switch, get some!)
Keyboard Connector Pinout
Keyboard and SDL Pinouts
M$ Elite Keyboard (Don't use it!)
Keyboard Emulator
Cleaning the Keyboard   (How to Open the KB)
   Socket Sizes Needed
Keyboard Error Codes
Speaker Grill
Sources for SDL to PS/2 Cables
Present Model M Manufacturer

Capacitive Switches
   A capacitive switch works when two plates (usually made of plastic) are connected in a switch matrix designed to detect changes in the capacitance of the circuit.
   When the key is pressed, the plunger moves the top plate relative to the fixed bottom plate. Usually a mechanism provides for a distinct over-center tactile feedback with a resounding “click.” As the top plate moves, the capacitance between the two plates changes and is detected by the comparator circuitry in the keyboard.
   This type of switch is nearly immune to corrosion and dirt. These switches are very resistant to key bounce problems that result in multiple characters appearing from a single strike. They are also the most durable in the industry—rated for 25 million or more keystrokes, as opposed to 10 to 20 million for other designs. The tactile feedback is unsurpassed because a relatively loud click and strong over-center feel normally are provided. The only drawback to this design is the cost. 
    Capacitive switch keyboards are among the most expensive designs, but the quality of the feel and their durability are worth it.

The following figure shows the pin numbering and signal assignments for the auxiliary-device connectors.

Pin	Signal
1	Data
2	Reserved
3	Ground
4	+ 5 V dc
5	Clock
6	Reserved

SDL = Shielded Data Link, a type of shielded connector created by AMP and used by IBM and others for keyboard cables

DIN	Signal	KB	+ DCv
1	+KBD DATA	B	4.8-5.5
2	Reserved	F
3	Ground	C
4	+5.0 Vdc	E	2.0-5.5
5	+KBD CLK	D	2.0-5.5
6	Reserved	A
Shield	Frame Gnd	Shield

From Peter
   Uh ... that's normal. System self-protection you know ... :-) The Elite Keyboard has a different keyboard ID than "normal" keyboards have - and it is intended for "ATX" machines AFAIK and behaves different after a power on.
   Most likely the 77 Lacuna keyboard controller gets a bit confused by all of that - and hangs the system.  Had that with several Cherry "space saving" keyboards with integrated trackball as well. 

From Jim Shorney
> I was wondering if anyone could help me with finding an inexpensive (i.e. >$20 or less) source for keyboard/mouse emulators. 

Get a cheap keyboard, take the microcontroller circuit board out, whack the cable to 6 inches or so, and reconnect the microcontroller board. Do the same with a cheap mouse.  Wrap in tape or put it in a small plastic 'project box' to insulate things.

From Bob Eager
   Remove the four hex head screws underneath (one needs a long thin hex socket). Detach the cable too. 
   Turn the keyboard the right way up, and remove the top half of the casing. All should be OK.
   I use a pastry brush to clean it. You can remove most of the keys (except for some of the 'long' ones which are best left alone). Be very careful not to squash the spring when putting the key assembly back. Best to tilt the keyboard, and let the spring 'fall' into the slot in the key as it is pushed in (try it and all will be clear).And take the keytop shells off to clean, of course

From Helmut P. Einfalt
   And after you've done that, put all keycaps into an old stocking (ask your better half if she has one with a ladder for you...), knot it so as to keep the contents as loose as possible, and take that bag as well both halves of the keyboard shell to the dishwasher.
   Yeah. True. Wash it with a standard dishwasher program -- you'll not recognize your keyboard afterwards anymore... (And yes, you must take out the electronic innards before washing). If you don't believe me, go ask Don Peter....
   Did that on the original PS/2 mouse, too.... Works like a charm.

From Peter
   Do *not* remove the lower part of the keycaps - only the upper part with the "lettering". The keycaps are a two-part assembly: the "pushrod" and the keycap itself. Remove all keycaps - be careful with the spacebar and the "bigger ones". 

Socket Sizes Needed
From Myself, god-Emperor of Microchannel
   I used a 7/32 socket- dunno what the metric size is. A Nutdriver or a deep socket.  I used an  Ace 1/4" Drive - 6 Pt. 7/32", 2021947. The important thing is something deep enogh to fut in the well that most of the screws are in.

From Peter
   I got a SKG (Made in Germany) No. 493, 5.5mm Chrome Vanadium. From the "tool wall" of our local super-market for about 3US$. Looks like a long screwdriver with a thin walled socket as tip. Works perfectly well since 1987 ...)

Dr. Jim
   Speaking of Snap-on, they do carry a nice long socket that works for these.  We bought one for our shop; not cheap, but worth it.  5.5mm, IIRC.

   The first series of the MF-keyboard called MF-1 which lacked the 3 status LEDs had in fact a speaker. It was designed for the XT family of IBM PCs and was intended to be used for "professional typists", which prefered to have a "click" in addition to the mechanical "keyclick" itself. There was a software available, which enables / disables the speaker click ... standard was "On" AFAIK. Worked with that thing for some time back in 1987 ...
   The MF-II design 101/102 keys *with* the 3 status LEDs inherited the entire case - and the speaker "grille" was left as an artifact and no longer used or needed. Guess it was cheaper for IBM keeping the old molding forms - and produce two keyboards on the same machinery.

One place that still carries them is Jameco
1334026   IBM PS/2 5' Coiled Keyboard Cable 2.95 (closeout)
1393120   IBM PS/2 10' Coiled Keyboard Cable  3.95