After you read this guide, you'll be able to fully clean an M2 keyboard, so when you find one for sale at a garage sale for $5 you can say, "Yeah, but all those stains..." and take it away for $2, knowing that only a couple hours' work later you'll have a like-new M2! Yeah!
For those wondering, today's keyboard is part number 1395300, manufactured in Feb of 1994. There are no detachable keycaps or drainage channels.
For those with no idea what this is about, the Model M and M2 are keyboards that use a buckling spring mechanism in each key to provide tactile and auditory feedback. When each spring buckles it makes a click, resulting in a machine-gun stacatto of clicky noise, as my wife can tell you. She's sitting two rooms away. Read more here:
Step 1: Unscrew These Screws
Step 2: Remove the Keys
Once you have the square keys removed, your keyboard should look like the 3rd picture. At this point, remove all keys except the space bar, keeping in mind that they will have rocker bars that may need to be gently pushed out with a driver or lonely mismatched chopstick.
Finally, remove the spacebar. In the 4th picture you'll see a little plastic spring molded into the piece. With a driver, pull that one way and then the other, freeing the retaining post on either side as you go. Click on the picture for details. Then pry the spacebar out from the bottom, in the middle of the bar.
Step 3: Naked Keyboard!
Step 4: Release the Latches
Step 5: Now What You Have Is a Mess
Now take the top piece and all the keys, and put them in a solution of warm water and dishsoap for an hour. Resist the urge to scrub, just let them sit. If you have tar stains or permanent marker, you may want to research other removal methods, but dishsoap will work for pencil, pen, and most other stains.
After an hour, break out a sponge and the q-tips and be as clean-freak as you want to be.
Step 6: Gimme Props!
Step 7: Don't Panic
Each key gets one spring, even if it's a big one. You can look at your keyboard, the electrical circuitry and the backside of the keys to figure it out for yourself, but here's a shortcut. Just follow the pattern in this pic and you should be fine.
By the way, here's the backside of the long Enter and + keys from the number pad. The spring goes in the top notch, not the fully enclosed one.
With the keyboard still inverted and resting on the props, click the latches into place. Now you can pick it up.
Step 9: Clean Naked Keyboard!
Then, put on all the larger keys, seating the bar first and then pushing down on the key. Your keyboard will look like the 2nd picture.
This is a good time to plug in your keyboard and make sure that you got the springs lined up correctly on the big keys. If they all work like they should, go on to the next step.
NOTE: if any key, space key or otherwise, doesn't go "clacky" like it should, pry it up and push down again. No need to do anything else if you have done all the other steps properly. I had to do this to one key about five times, so keep trying and it should work.
Step 10: All the Keys
Finally, screw it shut.
Woohoo, new M2! Time to post to eBay, or maybe you're feeling a little more selfish now that you've put all that work into it...
Step 11: If It Really Needs Cleaning
Lift on the circuit board while your partner releases the catches. The electronics meet the circuit board at the bottom end of the board, and are tensioned on with foam. You should be able to put this all back together easily, but I didn't want to go there. Good luck!
Step 12: A Note About Adaptors
Despite all the talk, I started cheap and ordered the one in the pic from this site (http://www.emtcompany.com/catagories/adaptors.htm) and it works just fine. Free shipping. Go nuts. YMMV.