I've been interested in TDD/TTYs recently and I've finally managed to get a working one. The above listing picture was really exciting to see, not just because it looks like it at least partially worked, but because I've seen similar units on ebay for a lot more than what I ended up getting this for.
Switches are short stem SMK vintage linears, it has a plastic plate and is really pingy. This is my first board with these I'm not really a fan of them. Smooth enough but low travel linear switches are not good IMO. The caps are really nice though, very thick and because this thing came with a case they aren't yellowed. The sublegends are typical of this sort of machine but of particular note is the slanted ! on the F key. This is to more closely mimic how it shows on the display since it uses a \ and a . together to form the ! from the segments available on the 17 segment LED. The slant on the cap is angled opposite from how it is displayed so it doesn't exactly work. Goofy but I can dig it.
As you can see from the case, they rebranded the machine at some point (the manual says as much) but I suppose they never rebranded the carrying case.
Now when I got this it was really dirty, with a ton of dust and pet hair underneath the caps. I was hoping that just compressed air would clean it off. The plate is untextured plastic so I was hoping that everything would blow out but after giving it a go there was still some stuff stuck to the plate. I tried getting it out with Q tips and iso but since it only has like 3 switches I decided it would be easier to desolder the switches and just scrub the top housing in the sink.
As you can see it has a stepped plate, which is a terrible design. I feel like it doesn't quite sit parallel with the desktop and it feels like all of the switches are sloped towards the back of the machine slightly. It feels off when typing and I don't like it at all.
Now even though the steps of the plate are roughly parallel with the desktop, the PCB is parallel with the top of the case.
So the switches just barely protrude through the holes in the PCB. Why they thought this was the way to go I can't say but whatever. I haven't ever seen this before and I won't mind if I don't see it again.
Earlier when removing the caps to try compressed air I couldn't get the spacebar off no matter how hard I tried, and now that I had the thing open I gave that a look too. No suprise that it involved further fuckery.
The spacebar stabs have what appears to be latex painted onto the joints and allowed to dry. This not only holds everything in place but also reduces stab noise almost entirely. It is honestly ingenious but it is a pain to have to deal with. It wasn't as gross as dealing with ancient dried lube so that is something. I didn't get good pics of it, but the stab inserts in the spacebar are metal that has been glued into the cap, so thats why I couldn't get it out, and on the ends of the stab wire there is a small length of rubber tube that is then latexed into the stab. Again, there is attention to detail here but why this particular solution.
With the space bar removed I can finally get at the switches for the space bar. It uses a stemless switch as well as a dummy switch, which apart from the dummy switch not appearing on the wiki at time of posting, really isn't all that noteworthy. It doesn't make any sense but at this point it isn't surprising to see stuff like that. The stemless switch is just as heavy as a standard switch and the dummy switch doesn't have a spring and is only there to provide a mount to hold the spacebar in place. I guess that they used a dummy switch with a spring in it for earlier models or when prototyping but decided that they didn't like how that felt? still weird that they didn't use a standard switch here. Also kind weird is the big foam squares to either side of the SB switches cover 2 more switch cutouts. Not really sure what you could need 4 in those locations so its weird to see them. I removed the foam and only when typing this up have I realized that I forgot to cover the holes up with something. whoops.
There are pads for a proper switch to be inserted in either position. They share the same position in the matrix so I suppose this is so that you don't have to pay attention when assembling as the proper switch will work in either position.
The dummy switch disassembled. really not much to it.
After cleaning it looks really nice and even if there are a lot of design decisions that aren't exactly what I would consider sensible it is still a really cool system. I need to mod push button into it so that the speaker only sounds with a handset setting on it, and it still needs some cleaning in places where the acoustic coupler foam/rubber needs replaced but it can't be removed non-destructively so I do not know how I will be tackling that particular problem yet. I'll probably try to find coupler parts and see if I get them to reasonably work in this case. If I can get another working TDD and a few of those retro handset for cellphones I could properly test this out and maybe use this between cellphones or voice chat in discord or a video game or something. Not really practical but it would be cool in a turbo nerd sort of way.
As a bonus, the case had the previous owner's wish list to Santa inside.