XL keyboard technical drawings

[+Stephen]

1 hour ago, JagChris said:

What kind of lube should be used?

Silicone - nothing with petroleum based oil, as that degrades plastic over time.

[+scorpio_ny]

Hi Everyone.! A while back I was doing a mylar swap to do a repair of a stock keyboard that had gone bad. I had some difficulties with it (some keys did not register), so I decided to revisit this project and to put some of the ideas I read online and some of my own, to see if  I can make this keyboard project more of a drop in friendly replacement (especially since I had extra PCB's I wanted to use😄).  While I was able to use use my previous versions the PH keyboard with my modified 800XL, it was really a tight fit and I was afraid that down the road the added pressure cause a fault  so I went to work and I wanted to share the was results:

Outwardly, It does not look like much different,  but some elements have been changed to make it more svelte to fit into the case.

 

Firstly, I had to find and source a lower profile MX switch that was compatible with the PCB. The viable option was the Otemu low profile MX switch. Here is how much shorter it is compared to a standard MX switch:

Three things about using this switch:

1.  It is three pin, so a plate is needed (no problem. I quickly redesigned the plate to accommodate for the lower profile)

2.  A caveat in using this switch is that it has less travel in the keypress since it is low profile.  To me, it was not that bad at all. To me, it still felt better than most of the stock Atari XL keyboards.

3. These switches are more expensive.

 

Unfortunately, the original switch adapters did not fit this stem design. I had wanted to rework the design anyway to see if I can make the adapter more sturdy in support of the keycaps.  This is what I came up with:

Top/side:

Bottom:

The one with four "arms" are for the function keys. It seemed to me that the function keys  posts was a little smaller, so I made it a little different and made sure it would not be mixed up with the ones for the regular keys. The new adapter also seems to work with fine with the standard MX switch:

I had then updated the keyboard mounting brackets so that the keyboard mounts more closer to the top case.  I initially did it so it was flush with the top case, but it did not look right. I then lowered it so that the keyboard would like it was an original part.

 

The final piece of the puzzle was the cabling. From a  post by someone here on Atari Age, I acquired  the ribbon cabling that was suggested. It worked great! To use this cable, I had to trim the corners of the insulation slightly so that it would fit into the keyboard socket. One thing to keep in mind is that  the cable is a little bit stiffer than the original cable so one needs to pay attention in closing the case so it does not come out of the socket.

The final tweak to reverse the M3 screw for the keyboard stab holders so that the flat head is at the bottom with they keyboard PCB to reduce the foot print even more. To finish the build, I covered the exposed metal parts and cabling with Kapton tape to prevent any accidental shorts.

 

I was actually able to install and use this keyboard with one of my Atari 800XL's with the shield still in place (yes, I powered it on and used it this way).  The only things left to do is to do some testing on the 600XL to see if there are any design tweaks are needed and the redesign of the mid supports for the keyboard PCB.  If anyone is interested, I would gladly post the links on where I got the parts and the updated STL files.

[_The Doctor__]

I hear the sounds of rabid hounds on the hunt for PCB, Supports, and STL. Hark, here comes one now. Blazer the Archer takes shelter...

[flemingt]

Hi @scorpio_ny great work carrying the concept forward. More than happy to host the updated files on the GitHub. I've lots of rev B boards left over so I might give this a go.

[+scorpio_ny]

13 hours ago, flemingt said:

More than happy to host the updated files on the GitHub.

Thanks @flemingt! That would be great if you can host the files. I am still doing more testing and I will post them shortly. I will supply some links for the the parts that I used and where to get them as well.

 

By the way, if you ever have some time and are working on an update to the design, it would be great if the updated board would have:

1. A placement for 1U keys on opposite sides of the spacebar. That way there may be a possibility to use third party keycaps (next to impossible to find a 9U spacebar)

2. Spacings to use a different type of low profile switches as well as the MX swtiches on the same PCB. There are other low profile switches that have an even lower footprint that could be good alternatives for those who want harvest their original keycaps and use adapters.

3. Spacings/holes for standard stabilizers kits if one want to use standard MX keycap replacements.

 

[+scorpio_ny]

Hi everyone! Sorry for the delay! I am still working on some adjustments on the keyboard mount. In my experimentation, it seems due to the differences in the cases for the 800XL and 600, the same keyboard mount does not work (since it is plastic and not thin metal).  I am working on one for the 600XL now. Still not there yet, but I am making progress. Here is the keyboard mounted in the 600XL with the latest version of the 600XL mount:

I still need to make some adjustments to the 800XL version as well. To help that along, I am building a second keyboard with all blue clicky switches. Also making some minor changes too. The length of the  ribbon cable in the original keyboard is not that long, so I ordered a five inch ribbon cable instead of using the eight inch cable to see how that works:

 

I will post more updates when I have made some more progress.

 

Thanks!

[+scorpio_ny]

Hi everyone!

 

Sorry for the delay! I have been busy with work and I have been going back and forth with some of the designs (and printing tons of plastic 😂). I am pretty sure that there can be more improvements, but I am satisfied on how the builds came out for now and I will work on it more over time. I will be posting the STL’s very shortly with links on where I sourced some of the parts for the builds. I will report some of my experiences, discoveries and tips while I was working on the keyboards. Here are some pics:

These three have mechanical keyboards. The top 600XL was done earlier uses standard MX Gateron brown switches with keycaps from “type 2” keyboard with Futaba switches. The bottom two were recently made with the Otemu low profile MX switches (mostly brown for 600XL and all blue for the 800XL) with keycaps sourced from “type 4” keyboard with Stackpole keycaps.

 

 

Here are some more pictures various points of the testing/build process.

Edited July 13, 2023 by scorpio_ny
Fix sentence

[+scorpio_ny]

Hello again!

Here are STL files that I used for the build  A couple of notes on the files:

1. There are two separate sets of files for the keyboard holder: one for the 600XL and one for the 800XL to account for the variance in the case designs. 
2. There are three sets of keycap adapters for the Stackpole (type 4 keyboard I believe). I recently discovered that the Stackpole keyboards had three type of key cap stems. The "Tall" one is for the the keycaps that have the slits top and bottom. The "wide" one is for the those keycaps that have the slits on stems on the left and right of the keycap. The "square" adapter is for the function keys, spacebar and in some variants for some of the modifier keys on the keyboard. These adapters will also work with the regular MX switches too. When attaching them to the Otemu low profile (LP) switches, press them to make sure that the travel is smooth. If not, it is because there me additional material or did not print correctly. Adjust or replace with one that does. When I print the adapters, I orient them with the MX switch connection at the top. I also print them at higher quality.
3. The spacebar stab holder was modified slightly to further minimize the spacebar rattling. Before using them to connect the space bar wire, take flat head screw driver to slightly open them up. The wire will connect more easily and securely. This version should also work with the earlier design with a regular MX switch. To secure to the keyboard PCB, you will need two M3 screws and nuts. When I use them, I orient the nuts on the top where the switches are.
4. The switch plates were redone thinner to accommodate the lower profile. On the option key plate, there is a small bump that indicates that is the top orientation.
5. I have yet to complete the work on the PCB middle supports, but I will soon.

Some notes on the parts that I used:

1. Otemu Low Profile Swtiches 20 Pack x 3. These are low profile switches that work with standard MX keyboards. The only drawbacks in using these switches are that they are more expensive than standard switches and since it lower profile they do not have the same travel as a full height MX switch. Also, it is strongly recommended that a keyboard plate is used since they are three pin, not five.
   US Amazon Link: https://www.amazon.com/OUTEMU-Profile-Switches-Thiner-switches/dp/B092JJNS19/ref=cm_cr_srp_d_product_top?ie=UTF8&th=1

2. Ribbon connectors (Thanks @Panther for this information!)
   The ribbon connectors work well and lets one use the keyboard without adaptes to connect to the Atari keyboard connector. You will have to use two of them to connect the keyboard to the PCB. Also, I had to trim some insulation between the connectors where they overlap so that they to not prevent connectivity. Also, before you solder to the keyboard PCB, make sure the exposed cable contacts are aligned with the contacts on the Atari motherboard (the connector is single sided) Also, the ribbons is thicker than the mylar and has less flex. When closing the keyboard, make sure that it does not accidentally come out of the connector when closing.

   Two (2)TE Connectivity AMP Connectors A9AAT-1208F 12-conductor 8" (the A9AAT-1206F 6" cable can also be used)

   Link for part: DigiKey US https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/A9AAT-1208F/151081

    

   For the function keys: A9AAT-0803F (3") or A9AAT-0802F (2"), depending on the keyboard

   Link for part: DigiKey US: https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/A9AAT-0803F/161132

3. Finally, I recommend that that the metal points on the bottom of the finished keyboard PCB is covered with insulation to prevent accidental shorts. In that end, I used Kapton/Polyimide tape

PH Stackpole to MX Switch Adapters 2.0.zip Spacebar Stab Holder 2.0.zip 800XL - Keyboard Holder - Otemu Swtich.zip 600XL Keyboard Holder - Otemu Swtich.zip PH Otemu LP Switch Plates 1.0.zip

[Panther]

Nice!  I really like my 800 Cherry keyboard, now I'm going to have to make one for my 800.  I knew I should have ordered a boatload of switches.  Thank you for sharing this.