356 Mini - The Lost Manual
(http://i.imgur.com/P07FMCB.jpg)
The OTD customs suffer from an extreme lack of documentation and understanding in the West. This is a real shame because I believe that the West has a growing appreciation for finely-made custom keyboards, yet there are valuable secrets related to pushing custom keyboard to their extremes locked away behind exclusive message boards and foreign languages.
The 356 Mini in particular has captured the vast majority of my keyboard attention for almost two years now. I use it as my daily driver, and yet I knew almost nothing about it when I recieved it, and still have only cobbled together what I now know through lots of guesswork, reading, and asking questions.
From what I've gathered thus far, it's one crazy little keyboard and it feels phenominal to type on.
This thread is my attempt to document all of the things I've learned about the 356 Mini in the hope that it might help other owners get more out of this amazingly stubborn and idiosyncratic keyboard, and log my progress towards understanding and appreciating the many design decisions made in such a small package. I of course welcome any corrections or additional info -- I don't speak Korean and have no real conduit to the Korean keyboard scene for any hard facts. Please help if you know more than I do! Especially if you have access to the original group buy or design threads on OTD.kr :D
Driving Goals:
☑ Replacement cable
☑ Reprogram layout
☑ Create new plate
☐ Replacement gasket
Table Of Contents:
1. Care & Feeding
2. Programming
3. Plate & PCB Design
4. Cable & Gasket
Thanks
This wouldn't be possible without a number of people who have helped along the way, either intentionally or otherwise, in alphabetical order:
BroCaps
Bunnylake
gundam
inornate
limitz
margo baggins
Mimic Cables
sixty
Care & Feeding
Cleaning Brass
I've found that a good solution for cleaning the brass of the Mini (and I'd imagine the other 356 boards) to be a solution of lemon juice mixed with baking soda. You should use enough baking soda to make the consistency of a gritty paste. Rub this on the brass with a towel of your choosing, then wash with warm water. Unlike Brasso or other brass cleaners this will not polish the brass, so it will retain its nice dull finish. I've also used a thin layer of olive oil to prevent tarnishing, however fingerprints will stick hard to it and tend to tarnish quickly (https://i.imgur.com/03vJ1Ig.jpg). Alternatively, people have used packing tape to prevent oxidation, however I'd recommend something with less sticky residue (some kind of 3M film perhaps).
Assembly
The tight tolerance of the keyboard mean that care should be taken during assembly. Specifically, I've found that the flexibility of the plate (and thus the harshness of bottoming-out on vintage Blacks) can vary if the plate and care are not put together evenly. I've had the most success by ensuring the case is upside-down and the top half is suspended so that the switches are off of the work surface I usually use two blocks of wood to rest the edges of the case on), then tightening the screws like you would a tire on a car: in a "star" pattern:
More
(http://i.imgur.com/XhEZ5Ag.jpg)
Additionally I'd recommend going over the pattern twice: once tightening loosely, leaving a gap in the case, then once again to tighten to close the case halves together. Don't over-tighten! The case halves should sit together completely flush with barely no visible seam, but the bolts don't need to be torqued down past that.
Plate & PCB Design
EDIT: 2023 update can be found here (https://geekhack.org/index.php?topic=87603.msg3171032#msg3171032)
I'm currently in the process of reverse-engineering the plate design of the Mini to create a replacement made of polycarbonate, and perhaps in the future a partial plate (the vintage Blacks in my board are plate mount and I'm quite partial to how they're tuned). The first prototype is on it way to me.
The major difficulty I've had is that the plate's switches are actually separated by smaller spacing than the recommended Cherry specs. Instead of the recommended 19.05mm distance center-to-center between switches, my current best measurements put the switches 18.875mm apart center-to-center, a full 1/8mm shorter than 19mm which is what I've heard is often used in rough switch designs. This can cause some keys to be *extremely* close to each other, but I've never had any issues with keys touching orrubbing. It does accentuate small tolerance differences between either the switch cutouts in the plate or the keycaps, and has been a bit of a worry in getting polycarbonate cut by waterjet rather than aluminum cut by laser. But in theory it pushes the boundaries of how small a 60% keyboard can be, and coupled with the large brass weight I suspect the Mini may be the heaviest custom by volume out there. I'd like to measure to get a better comparison to some other customs.
The plate is a sandwich design, so there are no screws that hold it in place. It instead has supporting "wings" on the top and bottom edges that fit between the top and bottom halves of the case and hold the plate in place. When properly assembled, this does seem to afford the plate a bit of flex, though I'm not sure yet what the tolerances are above/below the plate in the case's cutouts to hold the supports when assembled. I suspect there may be a bit of intentional leeway left so that the plate can more freely flex when the keyboard is assembled. This is because the keyboard is specifically designed to allow the plate and PCB to flex. This may be aided by the strange markings along the supporting wings which I have not found details of anywhere:
More
(http://i.imgur.com/3GIR9QJ.jpg)
These ridges on the wings appear to only be present on the V1 version of the Mini, the V2 plates I've seen have all been plain and flat. However I suspect the tapered edge of the "carved" wings may allow for slightly more vertical movement of the plate when flexing in the assembled keyboard.
The PCB is designed with a single long cut across the middle between the two bottom-most rows of alphas. It is accompanied by four small vertical cuts, one to the left of both the "A" and "Q" keys as well as between the ";" and "'" keys and between the "[" and "]" keys. The V1 and V2 plates may be slightly different, at least one V2 I've seen has only two cuts, the ones next to the ";" and "[" keys. These cutouts allegedly afford the special PCB to flex even more than normal, specifically with heavy linear switches in mind:
More
(http://i.imgur.com/AO49WAM.jpg)
(http://i.imgur.com/nzY64RK.jpg)
The first run of a polycarbonate plate for the Mini came in today. A little rough around the edges from the waterjet cutting by Big Blue Saw, but it should be easily smoothable with a little fine-grit sandpaper:
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(http://i.imgur.com/Ke1wuEW.jpg)
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(http://i.imgur.com/9PFfcsu.gif)
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(http://i.imgur.com/bBIaRcq.jpg)
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(http://i.imgur.com/Pz7tIgh.jpg)
Fitment of caps on the random bag of MX Reds from my Filco seems pretty dead-on for everything aside from the right Control, which is slightly too far to the right. It just barely rubs in the corner, but luckily I never use the right-hand mods :P I'm not 100% sure why its off but everything else seems to spot-on, it may be machining error, but I can't really see any other funky gaps along the bottom row. I think that hole is just slightly offset, it could be moved to the left in line with the other rows and look just fine.
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(http://i.imgur.com/0E8Ww47.jpg)
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(http://i.imgur.com/cEbvkeB.jpg)
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(http://i.imgur.com/rYKVG0Z.jpg)
Just to give a better idea of the tight tolerances this board works with:
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(http://i.imgur.com/cqzGdUu.jpg)
All in all I'm *incredibly* happy with how this one turned out. I was not expecting it to be so close on the first run. I'm going to sand it up and see how it looks, but I might not even bother doing another run.
I also did find that the bare plate sits very low in the case, the pins on the bottom row of switches rest on the bottom of the case. I think the gasket is really instrumental to the design of the board, as from what I've seen it rests on the bottom half of the case and pushes the plate to be flush with the top half.
I'd like to take some more pictures of that fitment and do some closer looking once I have it apart for a bit while I contemplate the desoldering process. From gundam's write-up it sounds like a) the PCB holes are very tight and b) the traces are very thin. Needless to say I'm going to be taking my time desoldering :-X
nice!!!!!
Managed to flash my mini to perform Left Fn & ctrl-caps swap.
Used USBasp (with libusb-win32 driver) for the programmer, plugged both port and pins, then flashed it using eXtreme Burner AVR.
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(https://i.imgur.com/5hnt2ed.jpg)
I've also attached my hex in case needed.
Hope it helps for future owner and thanks josh for the guide!
We've come a long way since this kind of flashing. Cool to see you got it working and didn't brick anything. :thumb:
Managed to flash my mini to perform Left Fn & ctrl-caps swap.
Used USBasp (with libusb-win32 driver) for the programmer, plugged both port and pins, then flashed it using eXtreme Burner AVR.
Show Image
(https://i.imgur.com/5hnt2ed.jpg)
I've also attached my hex in case needed.
Hope it helps for future owner and thanks josh for the guide!
Man i am so mad i didn't buy Cherry POM's when they where pretty obtainable back in the day. Awesome that you managed to flash it!
Attached is a half plate modification of the previously attached dxf file. The R4 mod key margins on the right side have also been corrected.
Note: I have only tested this plate on the UTD 356 Mini with a 6.25u spacebar, but it should support 7u. Please use at your own risk, I did my best to compare the plate to the UTD 356 Mini plate and everything seemed to line up exactly to the naked eye.
Plate was cut from the P3D store using frosted PC material.
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(https://i.imgur.com/xRSiabP.jpeg)
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(https://i.imgur.com/X2KK4ww.jpeg)
Awesome! Thank you so much for sharing! I need to give PC another try, I’ve been back on an aluminum full plate but I really love the feeling of soft poly with the o-ring mount.
Has anyone (with an OTD 356) confirmed if the UTD full and half plate `dxf`'s in this thread actually fit/work with the OTD 356mini (and the OTD 356 V1/V2 PCBs)? :)
(https://i.imgur.com/mrUd6K1.jpg)
I've been doing some experimenting with the various plates and PCBs I've collected over the years, probably owe this thread an update. A lot of what I've found is simply confirming what other folks know already, but I'll collect it here in summary.
In short, the UTD-based plates in this thread do not work with the original 356mini PCBs -- the switch spacing is slightly off.
However, the UTD-based plate attached to this post does work when used with a UTD-based PCB. I've tested this by mounting (not yet soldering) switches and caps in the attached plate with a Mechlovin UTD 356mini PCB. It all fits, though the USB port does stick out slightly from the case:
More
(https://i.imgur.com/JCv1ap0.jpg)
For folks with access to them, the plate and PCB made for the 356mimi by Vikipedeer also work in the original 356mini and the USB port positioning is the same spec as the original OTD PCB. However this was a fairly small run and extras are long gone.
Has anyone (with an OTD 356) confirmed if the UTD full and half plate `dxf`'s in this thread actually fit/work with the OTD 356mini (and the OTD 356 V1/V2 PCBs)? :)
Show Image
(https://i.imgur.com/mrUd6K1.jpg)
I've been doing some experimenting with the various plates and PCBs I've collected over the years, probably owe this thread an update. A lot of what I've found is simply confirming what other folks know already, but I'll collect it here in summary.
In short, the UTD-based plates in this thread do not work with the original 356mini PCBs -- the switch spacing is slightly off.
However, the UTD-based plate attached to this post does work when used with a UTD-based PCB. I've tested this by mounting (not yet soldering) switches and caps in the attached plate with a Mechlovin UTD 356mini PCB. It all fits, though the USB port does stick out slightly from the case:
More
Show Image
(https://i.imgur.com/JCv1ap0.jpg)
For folks with access to them, the plate and PCB made for the 356mimi by Vikipedeer also work in the original 356mini and the USB port positioning is the same spec as the original OTD PCB. However this was a fairly small run and extras are long gone.
Thanks for the update! I'm sure everyone appreciates it. In case anyone is unaware, Gondolindrim is trying to make replacement OTD plates/PCBs that will be backwards-compatible with OG OTD plates/PCBs. He asked me to spread the world about his efforts. He's on Discord: gondolindrim_
Has anyone (with an OTD 356) confirmed if the UTD full and half plate `dxf`'s in this thread actually fit/work with the OTD 356mini (and the OTD 356 V1/V2 PCBs)? :)
Show Image
(https://i.imgur.com/mrUd6K1.jpg)
I've been doing some experimenting with the various plates and PCBs I've collected over the years, probably owe this thread an update. A lot of what I've found is simply confirming what other folks know already, but I'll collect it here in summary.
In short, the UTD-based plates in this thread do not work with the original 356mini PCBs -- the switch spacing is slightly off.
However, the UTD-based plate attached to this post does work when used with a UTD-based PCB. I've tested this by mounting (not yet soldering) switches and caps in the attached plate with a Mechlovin UTD 356mini PCB. It all fits, though the USB port does stick out slightly from the case:
More
Show Image
(https://i.imgur.com/JCv1ap0.jpg)
For folks with access to them, the plate and PCB made for the 356mimi by Vikipedeer also work in the original 356mini and the USB port positioning is the same spec as the original OTD PCB. However this was a fairly small run and extras are long gone.
do you have a platefile that is 1:1 with your otd mini and works without any sanding necessary?