Cable for an odd Cherry ML Board...?

[Compgeke]

I picked up this odd looking Cherry board at a thrift store today for a whopping $1.50, not knowing what it was. It turns out to be a Cherry ML board, but looks a lot like a laptop board on a plastic frame with some sort of controller attached. Does anyone know if it's possible to make or obtain a cable for this?

The model number on the controller is "601-1853A" and the model number on the PCB is "G84-4107QAU / 02".

Here are some pics of what it looks like:

[Muirium]

Looks like it has indeed come straight out of a laptop. The controller is the odd part. Perhaps the empty socket has lines for PS/2 or even USB? (Both of those are 4 lines wide. I wouldn't expect USB however.) Alternatively, the occupied socket could well be connected to the bare matrix of the keyboard: just the ticket for a Teensy.

Cherry ML was designed for thin enclosures, so this board is definitely meant for either a laptop or a thin standalone keyboard. How much investigation into getting it up and running you want to do really depends on how it feels, I guess! ML is fairly nice, given its design constraints.

[Compgeke]

The matrix does run directly into the controller chip, so I can replace the controller directly. I started tracing what goes to what on the controller last night, but didn't quite finish.

[Halvar]

Could be just the innards of an older G84-4100 variant:

http://www.cherrycorp.com/english/keybo ... rial/4100/

I think it's not worth the trouble to teensy it, these go on ebay for quite cheap, and you can put the nice doubleshots (?) on any of them if you want to.

[Muirium]

ML doubleshots? Can't argue with that!

[Compgeke]

Well they aren't double shots, but either way I agree it isn't worth building a controller for it, as they're cheap enough used that I would probably spend more to make a controller than to buy a complete one, not the $1.50 thrift store one.

[Muirium]

And the matter of the missing case, of course.

[Daniel Beardsmore]

Interesting article number — 'QAU'? My ML4400 is pad printed and the article number ends in 'PPAGB', for pad printed, PS/2, A (?), UK ("GB"). QAU doesn't fit this pattern. 'U' is US, 'A' is always unknown, and Q …?

I've never heard of a laptop with ML switches. The customer number sticker is interesting, as is the irregular article number: I imagine that it has come out of some bespoke equipment.

[Muirium]

AU could be Australian.

Pity that laptops never got ML. I assumed that was the design goal. It's no surprise the sylph-like buggers don't have them now, but not even back when depth was still in fashion?

[Halvar]

So what printing technique are the legends? What is Q? Dyesubbed? They're not doubleshot, and they don't look lasered either. They don't have a protective coating, so I guess they're not padprinted. Do the legends protrude from the surface?

[Daniel Beardsmore]

Pad printing is demonised, so detailed knowledge about it is never disseminated. I've been trying to piece it together from what little knowledge does exist. Under [wiki]Keycap printing[/wiki] I've posted a few pictures that will help explain, but I can't authoritatively write them up as I'm only guessing here.

There appear to be different approaches. Old-school keyboards seem to use really thick, gloss black paint that was pretty durable, but would eventually start to wear off. You do still see this sometimes; Dell are currently using it with their Latitude laptops, although the printing process uses thicker paint and less precise application. One or more of these variants may use UV-cured paint, based on a suggestion from Matias.

Then you get the "decal" look of a thick layer of gloss sealant applied just around the printed legends, which is what most people think of by "pad printed". It looks absolutely awful.

Finally, you get subtle coatings. Filco (well, Costar I imagine) apply an overall coating so well that you can't even see it, although you can see the splatter on the inside of keycaps. With the G84 series, Cherry apply a coating over the top of the keycap, with a very narrow uncoated margin around the edge. The coating has a very fine halftone pattern. You can't tell any of this from photos; you have to angle the keyboard into the light, as the keycap plastic is much more reflective than the coating (normally the coating is much more glossy).

Those caps look the same as the pad-printed ones on my ML4400.

[RC-1140]

Pad printing on G84 keyboards can be very bad. I have two G84-4100, the padprinted one has very worn down legends.

The color of this keyboard reminds me of the dyesubbed G84-4100 SPAUS keyboards which surfaced some time ago. They were winkeyless and they mostly look the same. I would thus suspect that these might be dyesubs.

I can recognise these Cherry ML dyesubs from their feeling alone. The dyesubs feel very "smooth" on touch. The pad printed ones feel more rough (when the coating is still intact) or slightly "sticky" (when the coating is missing).

Edit: I just found this picture on kbdmania:


Apparently the grey color isn't exclusive for PBT dyesubs. But in the pictures one can see that the material is marked on the bottom. Some of the keys have a PBT/ABS marking underneath. Not all though.

[Compgeke]

The bottoms of mine say ABS. Mine also aren't pad printed, although if they are they did a great job as the legends are completely flush with the plastic, unlike most cheap pad printed boards where you can clearly tell they're printed.

I'll be able to get some pics tomorrow, I'm currently charging the camera and flash batteries.

[Compgeke]

Actually, pictures!

The ABS markings on the bottom:


The key legends:


And as opposed to the Thinkpad T410 keyboard (which is printed):


And something else random: I have this keyboard on a no-name (literally no branding, anywhere, not even when powered on) 386 laptop, which has a layout almost identical to the Cherry ML's layout...but isn't a Cherry board? I got these both at the same time, and only got the Cherry board as it looked like it would be a replacement for this board, but it isn't.