So I went ahead and replaced all the switches on my Omnikey Ultra with Matias clicky switches, and I've been using it for a week. I couldn't be more impressed -- the switches are very smooth and tactile, and maybe just a tiny bit lighter than the original Alps switches. The whole keyboard types at least as good as new, and since it's got the layout I like and it's built like a tank, it's regained the spot as my favorite keyboard of all time.
For anyone with an old Northgate or Avant keyboard where the switches have gotten stiff, sticky, bumpy or just don't feel like new anymore, I highly, HIGHLY recommend the Matias switches to breathe new life into it. I'm really surprised lots of people haven't been doing this already, but maybe there just aren't that many of these keyboards around anymore
Here's the story of how the switch-swap went, for anyone else who might want to do this:
I took off the cover before taking the keycaps off -- it seemed to make it a little easier to get the caps off. And for the 6 keys with those little stabilizer bars built in (the space, Enter, backspace, left shift, keypad Insert and keypad Enter) I slid a screwdriver in and popped the stabilizing clip out first before removing the keycap, in an attempt to avoid damaging the little black plastic holders that hold the metal stabilizers in place.
After getting the caps off, the next step was to unsolder the old switches. This generally went pretty easily using this nice
solder sucker from All Electronics. Unfortunately a bunch of the switches were installed with their solder tabs bent over, which seemed totally unnecessary and caused a bit of extra work -- I had to first pry the tabs up while melting the solder, then melt it again to suck the solder out.
I should also note at this point that I had already replaced a handful of the switches with the Matias clicky switches as an initial test, and I left those in. This meant that the keyboard PCB stayed attached to the metal plate the whole time, which seemed to make the reassembly easier -- I didn't have to worry about the board flopping around while I put the first few new switches in. The downside is that it was a little more work to blow all the dust bunnies out from between the metal plate and the PCB, but it still wasn't too hard to get it cleaned up.
After getting all the remaining old switches out and making sure the PCB holes were clean, it looked like this:
Putting the new switches in was a piece of cake -- they just dropped right in and stayed perfectly in place, so I didn't need to bend the solder tabs over. The only exceptions were the Insert and Delete on the middle keypad -- for those I put each switch in place, turned the keyboard upside-down and set it down on a pair of needle-nose pliers with rubberized handles, so that the switch was resting on one of the handles. This held the switch in place to be resoldered. Here's the keyboard with a full set of new switches:
After getting all the switches soldered in, I put the keycaps back on. This generally seemed to require more force than with the original Alps switches -- maybe the Matias slider holes are a tiny bit tighter? Or maybe it was just because they were new. I had to wiggle each cap back and forth against the slider in order to get it started. Then, in order to avoid stressing the PCB and getting any cracks in the traces, I pushed against the back of the PCB while pushing each keycap on until I got that satisfying "snap!" when the keycap seated.
After that, I just bolted it back together and started enjoying typing bliss :-)
Here's the "before" picture, which is about the same as the "after" picture would look:
Bottom line: if Matias ever makes a keyboard with the Ultra layout I'll still buy one, but until then this is the next best thing!