Need help with an ALPS white switch

[cfraser]

Northgate Omnikey Ultra, Backspace key. It has gone a bit wonky, seems to require me to push slightly forwards on it to register correctly/reliably. This switch is installed upside-down compared to the regular-sized keycap switches. I took it apart and "cleaned" it (it wasn't dirty...).

So considering its mounting, I can see that slightly pushing forward would move the switch contacts slightly forward towards the plunger, enabling more positive action. At least that's how I'm explaining what I see... Does that make sense, and how can I fix it? Worst case I'll just disassemble the beast and IDK, maybe swap in the OMNI switch. Thanks.

[I wish I could say otherwise, but the BS key is possibly the key I use almost the most, so this is a problem.]

[Mattr567]

Northgate Omnikey Ultra, Backspace key. It has gone a bit wonky, seems to require me to push slightly forwards on it to register correctly/reliably. This switch is installed upside-down compared to the regular-sized keycap switches. I took it apart and "cleaned" it (it wasn't dirty...).

So considering its mounting, I can see that slightly pushing forward would move the switch contacts slightly forward towards the plunger, enabling more positive action. At least that's how I'm explaining what I see... Does that make sense, and how can I fix it? Worst case I'll just disassemble the beast and IDK, maybe swap in the OMNI switch. Thanks.

[I wish I could say otherwise, but the BS key is possibly the key I use almost the most, so this is a problem.]

Bad switchplate, its how most Alps fail. You can get a replacement switch fairly easily. Just make sure it's the right kind (pine or bamboo).

[Daniel Beardsmore]

The switch shouldn't move, so I assume that any movement is very subtle!

The actuator leaf spring may benefit from being gently adjusted — it may have become too straight, and need to be corrected back to its original angles.

Bendibus maximus — caveat: drawn left-handed in MS Paint 2D

bendibus.png (12.48 KiB) Viewed 4985 times

It's fairly easy to slip this part on and off, and you can test the switch by inserting just the spring and slider to see if it registers, before reassembly.

[2ZQ]

I have had boards come in with the simplified and complicated versions both failing. Simplified seems to be more prone (fukka). I usually just switch it with a modifier and then replace the modifier with a skcm (to fit the feel of the board). Sometimes I get carried away and replace the whole board if they are simplified, because my fingers are weak after work. I also like my board to feel like butterfly wings.

[cfraser]

I also like my board to feel like butterfly wings.

I have a keyboard you'd probably love the feel of, it's my favorite keyboard, though I suppose it's not technically "mechanical" as maybe most people here would call it, and it's only ASCII output so I can't use it straight with a PC. I describe it as it's like your fingertips are dancing on little pillows, it's almost irresistable and sensual, you want to type on it even if you have nothing to type, it feels that good (to me anyway).

It's a Micro Switch SC type, I purchased it OEM from Honeywell in '83, and it's not at all like the wiki describes SC switches here (it's S/N 9, so things may have changed afterwards). Plus it's virtually totally silent in all ways, barely even a sound from keys "bottoming out". [I guess it would be almost trivial to make an ASCII to PS/2 or USB converter for it, but even though it's 103 keys, it doesn't have many of the common keys modern KBs have, and some of the keys are placed differently (like the cursor and editing key bank is off to the left). It uses an 8748 micro, so could be custom programmed.]

[cfraser]

The switch shouldn't move, so I assume that any movement is very subtle!

The actuator leaf spring may benefit from being gently adjusted — it may have become too straight, and need to be corrected back to its original angles.

It's fairly easy to slip this part on and off, and you can test the switch by inserting just the spring and slider to see if it registers, before reassembly.

I wasn't kidding when I said I use the BS key a lot, especially when you consider that after 25 years (??, roughly) of use, the BS key is the only one that's ever needed the slightest bit of attention. Anyway, I fixed it, after about a half-dozen more attempts. Whatever I thought I was doing by very slightly putting forwards pressure on the switch, I actually had to do the opposite to the switch part of the keyswitch to fix it, that's why I couldn't fix it a first.

I think you're correct with what you said above, but it wasn't the problem in this case. I didn't have to bend any of the leaf springs (tried that to no avail). What worked was moving the internal switch assembly very very slightly backwards (towards the nearest shell side). Perhaps the way I naturally type/hit the BS key, and the way it's angled, pushed it forward over the years, IDK. Once I got the key working properly, I disassembled again, put in new/spare shell and leaf/coil springs, and hopefully good for another 25 (as if I am...).

On a slightly different subject, I see it commonly said on the web that on the stand-alone leaf spring, 4 tabs = silent, 2 tabs = clicky (like the Omnikey Ultra). IDK where this came from. I mean, you can't remove clicky because you can't add two tabs if you only have two to start with. The way to remove clicky without getting new springs is to very slightly straighten out the two "hooks" on the stand-alone leaf spring. Just flatten a bit, remove the obvious hook aspect, so you can put the bends back if you don't like silent/clickless.

[I had no idea there were "keyboard forums" and enthusiasts until a couple of days ago when I needed to fix this BS key. I was a KB maniac back in the day, early '80s, I tried all sorts and have lots of different types, especially from Micro Switch/Honeywell who I seem to have had a thing for, judging by the amount of oddballs I have in my "old KB" box.] Thanks for everybody's help/interest in my problem.

[Daniel Beardsmore]

It's a Micro Switch SC type, I purchased it OEM from Honeywell in '83, and it's not at all like the wiki describes SC switches here (it's S/N 9, so things may have changed afterwards). Plus it's virtually totally silent in all ways …

I did encounter what was either an ST with an SC sticker or vice versa, so maybe there was a bit of confusion at Honeywell. Of course, you're not going to leave us all wondering about it now, are you?

I think you're correct with what you said above, but it wasn't the problem in this case. I didn't have to bend any of the leaf springs (tried that to no avail). What worked was moving the internal switch assembly very very slightly backwards (towards the nearest shell side) …

The internal switch assembly is a tight fit, and I can't imagine it moving enough to be of any significance — if that were the case, then the legs would be a bit wobbly. Very odd!

[cfraser]

It's a Micro Switch SC type, I purchased it OEM from Honeywell in '83, and it's not at all like the wiki describes SC switches here (it's S/N 9, so things may have changed afterwards). Plus it's virtually totally silent in all ways …

I did encounter what was either an ST with an SC sticker or vice versa, so maybe there was a bit of confusion at Honeywell. Of course, you're not going to leave us all wondering about it now, are you?

I think you're correct with what you said above, but it wasn't the problem in this case. I didn't have to bend any of the leaf springs (tried that to no avail). What worked was moving the internal switch assembly very very slightly backwards (towards the nearest shell side) …

The internal switch assembly is a tight fit, and I can't imagine it moving enough to be of any significance — if that were the case, then the legs would be a bit wobbly. Very odd!

Yes, I just barely moved the ALPS internal switch assembly, but it did move a tiny bit, enough to make a difference anyway, I could see it move it's right against the shell now. I do know the switch assembly itself is extremely particular/precise and easy to mess up. The other parts of that switch were all new/stock/unmolested by me, so they had nothing to do with the fix, I added them afterwards just to say "it's well done!".

That Micro Switch KB is a 103SC56-1, build date 8310, S/N A00009. Definitely SC as all the custom parts are labeled SCxxx. There is *zero* feedback of any type from the switches, you just have to have faith... The shape/size of the keycaps and feel of the springs is very pleasant...seems weird to say, but you guys get it. I recall going to a lot of trouble, and expense (for me at least, at the time) to get it. Actually, I just recalled my GF at the time worked for Honeywell, and she couldn't even help me. Totally forgot about that. Memories... I must have quite a lot of documentation for this KB, somewhere, as I didn't order/"specify" it in a vacuum, and I did use it with a custom-design/built computer (Z80) so I had to do the interface myself. I remember I was obsessed with their Hall effect keyboards then too, but totally failed with ever getting a satisfactory (to me) interface, they were not simple to work with and for some reason I couldn't get one with the interface circuitry built in (still have a box of their "raw" Hall effect KB assemblies somewhere here).

[Daniel Beardsmore]

It needs pictures. Inverting spring switches tend to be very loud, although Alps SKFF (vertical plate spring) seems fairly muted, which was a real surprise. It should be louder when mounted into a keyboard though. You just can't take a piece of flat metal and invert it without a noise, so yours either is an ST (with rubber domes), or they've done something pretty amazing to cut down all the sound. I've seen a video of an SC and it is indeed very loud.

[cfraser]

^ The only "noise" is from the springs pushing the keycaps up when your finger is removed, the springs are fairly strong and the keycaps are kind of lightweight, significantly larger than e.g. the Northgate's regular-sized caps so more "hollowish". Not great quality keycaps compared to other MS KBs I have. You can see the metal plates and membrane in unused switch positions, I think it looks like the wiki's pic, I'll re-check in a minute. [Edit: nope, must have seen the pic somewhere else, so IDK at this point.] Maybe I'll take one of the switches apart to see how the mechanicals are, have never done that. [I have other ("truly") capacitive membrane keyboards of the era and they are 100% silent, even less mechanical than the SC. They were intended for harsh environments, totally sealed. About as pleasant to type on as a touchscreen...]

[Daniel Beardsmore]

SC and ST series are still very poorly understood as they are quite rare. It's not proven that "ST" means "silent-tactile" and maybe that's a marketing adaptation instead of a definition, as there seems to be some SC/ST crossover.

The Hall effect type that interests me is SN series, as it's like SW but not quite the same, and we don't know if it's still dual magnet. I'd assume not, as I would imagine that the need for two huge magnets became obsolete long before then. RAFI's switches use a teensy little magnet.

[seebart]

I'd love to see some pictures of your Micro Switch KB 103SC56-1 cfraser!

[cfraser]

Man, am I ever way OT now... I found the "engineering drawings" for the 103SC56-1, 6 pages includes schematics. I guess I can't take a switch module out after all, but I can see the "plate" in each switch that the actuator moves is copper-colored (i.e. looks like phosphor bronze, not saying it is for sure), and there's no click or tactile feel at all. Regular switch modules are SC-10090, modules with an LED are SC-11002 (there is another version of this module, SC-10109, not used here). Membrane assembly is SC-25203, detector chip is SC-23011 (switch scanning matrix connects to this). There is no rubber anywhere! They claim NKRO, but then mention any more than 6 keys in the same row or column (of the scanning matrix) pressed at once may cause errors. Keycaps have very nicely molded-in legends (very neat from the underside, compared to e.g. the Northgate). Also has serial output, which I never used (additionally, a D-sub connector is optional). Assembly has positions/electronics for up to 126 keys.

The docs I have are obviously photocopies, and parts are already difficult to read, so I don't know how well a scan would turn out...also, they say they're the property of Micro Switch/Honeywell and can't be reproduced without permission...don't know if they'd really be of any use to the community if somebody wanted to host them for whatever reason... Pics should be fine. Later I'll see if I can find the actual catalog where the switch modules are defined, I must have it somewhere as I was very particular about getting all the deets back then when pretty much everything home computer-wise was still largely DIY.

[Daniel Beardsmore]

I'm wondering if SC/ST refer not to the actuator design, but rather simply to the use of membrane sheets.

[2ZQ]

That old honeywell sounds lovely! would love to see some pictures of your collection if you have the time to make a post.

[cfraser]

I'm wondering if SC/ST refer not to the actuator design, but rather simply to the use of membrane sheets.

I got to thinking along similar lines, that SC or ST might be more general purpose designations for "something". e.g. I thought the "C" might stand for capacitive. Clearly the various switch components could be used in any frame, and it would be the membrane that would partly form the switch characteristic, as well as the spring and metal actuator. I was hoping to find the actual catalog I ordered from, but I may not easily do so because I have no idea if it was from an MS/Honeywell one, or from datasheets because I bought it at a large local (non-chain/franchised) distributor who didn't have catalogs IIRC. [Sorry first time posting pics here, I didn't do it the way I wanted, they're in reverse order from what I intended...]

[Daniel Beardsmore]

Double-shot moulded keycaps are only known to have used two materials historically: ABS and Tenite. Comptec/Signature Plastics always used ABS. Cherry used both ABS and Tenite. I'm assuming that Tai-Hao (who made the Northgate keycaps) always used ABS, although they now offer PBT double-shot keycaps (with the first shot, the legend, being POM I think). Micro Switch keycaps are held in high regard, but nothing is known about them.

It's hard to make the switch out in the photo, but indeed it seems to be something we've never seen before. Just to be clear, is this linear or tactile?

(There's a "Place inline" button for images for putting them into a topic, and you can do this in any order you like; I don't know why phpBB insists on reversing the image order, but since new forum software is in the works, it's no longer worth worrying about this idiocy, unless we get a newer phpBB that's still as frustratingly stupid.)