This is nowhere near complete or authoritative yet... just wanted to throw this out there because I've discovered a couple things that are likely obvious to more experienced keyboard modders but I had to figure out on my own (but would have already known going in had I found it in a search before starting.) Most of this is probably applicable to pretty much any plate-mounted Cherry MX board.
Opening the case: 104 is similar to tenkeyless apparently, it's similar to the procedure shown
here - basically the hard part is releasing the tabs on the front of the case. You think you're going to break it, but you're not. Basically, when you remove the three screws on the bottom (the center one is under the small round OK seal that you're not supposed to break or you'll void your warranty... bah! who needs warranties?) the rear of the case will be free but the front is still held in place by four catches. What you need to do is slide a small but dull object, like a non-serrated butter knife, in between the case halves and pry the top pretty much straight out (towards you as you sit in front of the keyboard in a normal typing position.) Once you get the idea down, it's easy.
When removing the switches, after having tried to remove the whole PCB without removing the switches, I can say that the ONLY way that this is going to work, is to desolder each switch individually and then pop it out of the plate and PCB. The catches that you need to hit with a small screwdriver to release the switch from the plate are on the top and bottom of the switch. So you'll probably want to remove the keycaps before you start, and also have a container handy to throw the switches in, unless you are changing stems one by one (which is also an option, I suppose.) However, if you get a wild hair and think you may want to paint the plate a la some of the flashier new keyboards on the market, then you'll definitely need a container :/
When desoldering, I was using an Edsyn Soldapullt hand operated desoldering pump. Unfortunately I'd never used one before nor did I have anyone around who had to show me how it was done. So I had to figure it out from trial and error, and with the help of some posts here. Anyway, here's what worked - set soldering pencil at about 650F or a little higher; retin tip before each terminal. Heat solder until melted. With pencil still on solder joint, hold Soldapullt in left hand, set tip as close as you possibly can to solder joint/pencil tip and press the release. Repeat for the other terminal. Try to remove switch. If it doesn't work - don't force it. Take some good old fashioned 60/40 or 63/37 solder, resolder the connection, and then re-desolder it. I can't explain why, but the old style leaded solder, aside from melting at a lower temperature, also just seems to be all around easier to work with than the RoHS stuff that's being used on all new electronics today. Fortunately leaded solder is still being sold (that is, unless you're doing this all day every day in your basement, in which case you probably should consider investing in some more sophisticated equipment so you can actually get good results w/o sucking in too much lead) A few of the switches were still slightly stuck because the tabs from the switches were resting against the PCB, so no amount of sucking of solder was going to break them completely free. What I did in those cases was to gently pry the switch from the bottom (side away from the terminals) until the catch released, then from the backside, press gently on the black plastic protrusion through the PCB while holding the iron on one of the tabs and then the other. When I felt a little "pop" then I knew that I'd broken the solder joint and was able to then release the other catch and remove the switch. In some cases probably due to a little ham-handedness on my part, the little "sleeves" came out of the PCB either whole or in part, but I never lifted any pads. This seems to have no effect on functionality; I did not remove the PCB to see if there were any traces on the top side of the PCB, but there were definitely none connected to any pads on the top side where the switches attached, and since everything tested perfectly OK after I reassembled (although I did try to get lots of solder on the terminals just in case) I suspect that the only traces are on the bottom (keep in mind that I'm referring specifically to a Filco here and not any other board.)
I can't believe that I'm going to say this, being a notorious cheap b*****d, but the tediousness of this whole procedure is starting to make me think that unless you're doing ergo clears or some other custom switch it might almost be worth it to order brand new switches. But then you still have to lube them somehow, so... still tedious.
The good news is that after all that work, the board is back together and is working well. I didn't take nearly as many pictures as I probably should have, but will try to upload some later. I'll see if I can get a helper to take a video as I change the space bar switch in my WASD keyboard (same basic idea, it's a plate mounted MX board) because if a picture is worth a thousand words, a good video is worth much more... Now that I've got the system down I can actually do this fairly easily and hopefully without embarrassing myself in public...)
