Repairing a Unicomp Spacesaver-M

stratokaster · 16 Oct 2018, 17:49

Hello.

I have a relatively old Unicomp Spacesaver-M keyboard (made in 2011), which developed a fault about 3 years ago: several keys (`,q,a, z and left Command) stopped working, presumably due to some problem with a membrane. Since then, the keyboard has been in storage.

I took it from storage today and tried it with my MacBook Pro only to discover that it now doesn't work at all. When I plug it in, both LEDs (Caps Lock and Fcn) briefly flash, after this the keyboard constantly outputs the "/" character and that's it.

I'd like to save this keyboard because I like its bottom row (with 1.25u Cmd and Opt) much more than modern Unicomps (with 1.5u Cmd and 1u Opt). I wonder if it's likely to be difficult repair... I know that I have to dismantle the main assembly and screw mod it in order to repair the membrane, but I now suspect that the controller may be out. I wonder if Unicomp sells spare parts for this keyboard.

paddle0 · 17 Oct 2018, 13:57

Unicomp seems to offer a lot of parts & other stuff that aren't listed on their website. I'd contact them.

I like Unicomp keyboards a lot, and I agree that 1.25U bottom row modifiers are best. But I'm not a fan of the Spacesaver M in particular because I don't like that I have to hold down Fn to use the numbered function key row as standard function keys, and not as media keys. Like MacBook built-in keyboards.

Also, if memory serves, Spacesaver M uses Apple's *old* media key layout. Not great!

stratokaster · 17 Oct 2018, 14:16

Thanks, paddle0! I agree about the F-key arrangement, but I think it's possible to remap them using Karabiner-Elements (I'm not exactly sure because I haven't had this keyboard working properly for a long time).

I think the right way to approach this repair would be to open it up and see how the controller behaves without the mebrane connected to it; I would also need to look for individual part numbers for the membrane and the controller.

Muirium · 17 Oct 2018, 14:20

Could well be the controller. Do you know if the column and row ribbons that come off the main assembly are compatible with Phosphorglow's replacement Model M controllers? I've got a USB B model of his lying somewhat spare.

stratokaster · 17 Oct 2018, 14:23

Thanks Muirium, I don't know for sure, but I think all their membranes should be compatible, with the sole exception being Unicomp M122. I will know for sure when I get back to Ireland where I have a proper 5.5mm nut driver to open this thing up

Muirium · 17 Oct 2018, 14:26

Cool. PM me if and when you fancy it. The beauty of Phosphorglow's controller is it's entirely reprogrammable. I've got it running Soarer's controller because I'm used to it and can understand how to define its macros. Very handy.

That one's spare because I replaced it with his subsequent micro USB version. And I live in hope for an FSSK reboot besides…

stratokaster · 17 Oct 2018, 14:47

Thanks Mu!

stratokaster · 21 Oct 2018, 17:31

I found a 5.5mm nut driver here and opened the keyboard today. I was able to confirm that the controller is in fact working perfectly.

The problem lies in the connection between the controller PCB and the membrane. They're simply pressed together and held by a couple of extremely tiny screws. There is some foam-like material on the underside to create even pressure on the connector, but it was mislocated in my keyboard. In addition, the screw holes on the PCB are too large and the screw heads go right through them. Great design, Unicomp!

In my opinion, this keyboard was engineered to fail. By carefully applying pressure to the controller PCB I was able to make different parts of the keyboard work. However, I was not able to get all of the keys to work, despite gently cleaning the pads on the PCB and the mebrane with a rubber eraser and aligning the membrane and the PCB to the best of my ability.

Other observations: the keyboard is only 7 years old, but it's already shedding rivets; the backplate/membrane/barrel plate assembly used to be held in place by a piece of double-sided tape, which has degraded over time and now the assembly is sliding freely inside the case. Great design, Unicomp!

I'm kinda tempted to harvest the keycaps from this keyboard and get a proper IBM-made Model M as a replacement.

stratokaster · 21 Oct 2018, 17:45

Another question! I'm located in Europe and I'm mostly seeing ISO Model M's for sale.

My understanding is that all Model M membranes and barrel plates are universal, and it's easy to convert an ISO Model M to ANSI by installing stabilizers, hammers and keycaps from an ANSI model. Am I right?

stratokaster · 21 Oct 2018, 18:19

stratokaster wrote: ↑I found a 5.5mm nut driver here and opened the keyboard today. I was able to confirm that the controller is in fact working perfectly.

The problem lies in the connection between the controller PCB and the membrane. They're simply pressed together and held by a couple of extremely tiny screws. There is some foam-like material on the underside to create even pressure on the connector, but it was mislocated in my keyboard. In addition, the screw holes on the PCB are too large and the screw heads go right through them. Great design, Unicomp!

In my opinion, this keyboard was engineered to fail. By carefully applying pressure to the controller PCB I was able to make different parts of the keyboard work. However, I was not able to get all of the keys to work, despite gently cleaning the pads on the PCB and the mebrane with a rubber eraser and aligning the membrane and the PCB to the best of my ability.

Other observations: the keyboard is only 7 years old, but it's already shedding rivets; the backplate/membrane/barrel plate assembly used to be held in place by a piece of double-sided tape, which has degraded over time and now the assembly is sliding freely inside the case. Great design, Unicomp!

I'm kinda tempted to harvest the keycaps from this keyboard and get a proper IBM-made Model M as a replacement.

I also think I found the broken trace on the membrane that was the initial problem: in Spacesaver-M (and also in Ultra Classic I presume) the backplate leaves the membrane partially exposed on the left hand side, and when the keyboard is assembled, this part is pressed against two narrow supports on the bottom case. Guess what happens next...