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archeocomp

1mm FFC Keyboard Cable and Adapters

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I've got a 600XL off eBay sold as not working. To my surprise it was working fine but keyboard cable and connector were damaged beyond repair. So I designed (in march!!) solution around 26pin 1mm FFC cable used commonly for notebook floppy drives, as I happened to have both connectors and cables already in my supply. There are adapters on both sides of cable from 2.54mm -> 1mm

 

Adapter on keyboard is made be PCBWay from 0.6mm substrate. It took more than 2 months to arrive btw..

 

I tried two adapter(s) for motherboard. Green one is also 0.6mm PCBWay with through hole components. Brown one is OSH Park Flex PCB which is only 0.1mm thin!! It is probably thinner than the original flex cable Atari used. They both work. But I will stick to OSH Park material. 600XL is now sound and happy.

 

I think I will let OSH make also keyboard side adapter from Flex. Currently I can still insert sheet of paper between keyboard platics and top side of the ffc connector. With Flex it would be much more space left. If there is interest I will publish all the projects.

 

FFC cable is 20cm, Atari original was 15cm.

 

 

ffc1.jpg

ffc2.jpg

ffc3.jpg

ffc4.jpg

Edited by archeocomp
typos
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This should also work with 800XL too.  With minor changes if at all.  Please publish info if you are willing.  🙂

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https://www.pcbway.com/project/shareproject/Atari_600XL_keyboard_adapter_to_1mm_pitch_FFC_cable.html

https://oshpark.com/shared_projects/2DM5q3aX

 

Schematics is trivial, all resistors are 470 (1206), except R21 which is 3.3 Ohm (reset line). FFC cable and connectors are 1mm pitch, 26 pin. (floppy drive type) If you will use reversed cable, you will also need two different types of connectors (bottom and top contact). With a non reversed cable, the same connector type will be used.

I have used round pin header to make soldering keyboard side adapter a relaxing exercise. Than just cut off what was no needed.

600xladapter.jpg

s-l400.jpg

Edited by archeocomp
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On 7/5/2020 at 3:53 PM, Roydea6 said:

@E474

 

Is doing something along this line of key board fixes also.

Correction it is @Level42

 

Yes. My solution uses an even smaller flex cable but that's not very relevant. At this moment I have new flex cables arrived and PCBs and the connectors still on order. I have adapted the PCB so that it could also be used in XE's, mostly this meant there are now two break-outs for the keyboard-connector so that this can be hooked up as a 2nd button for any joystick/pad that offers that. This is very useful for games like Dropzone etc. where keyboard is a "bomb" option....also the new Scramble f.i.

Sets will be available as soon as I received the PCBs and connectors. I decided to do the soldering myself. Having the connectors installed is making things way too expensive.

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FYI the 600XL keyboard works fine without the intermediary resistors

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16 minutes ago, archeocomp said:

I was unsure, so I did put them in:-)

Glad you did, your Atari keyboard thanks you.

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On 7/8/2020 at 10:07 AM, _The Doctor__ said:

Glad you did, your Atari keyboard thanks you.

 

Hey @_The Doctor__, this one goes back a while, but I'm working on repairing my keyboard now, so I'm just looking into it.

 

I have to ask, since there are no resistors or anything but a straight ribbon cable from the keyboard to the motherboard originally, why would the Atari care one way or the other about these resistors? What purpose do they serve? I'm just curious what I'm missing.

 

Edited by bfollowell

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The resistors are current limiters, in case of shorts. All models have them on the motherboard, except for the 600XL. They have a small PCB insert which has the resistors on it, before it goes to the mylar.

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45 minutes ago, ivop said:

The resistors are current limiters, in case of shorts. All models have them on the motherboard, except for the 600XL. They have a small PCB insert which has the resistors on it, before it goes to the mylar.

 

OK, I get that, but from the looks of it, this mod just ties in where the mylar connects to the keyboard, or replaces it. The other end attaches to a card connector that plugs right into the original keyboard mylar connector on the motherboard, so the motherboard's resistors would still be there, so I'm really not sure why anything would be required on one of these boards. It seems like they'd be redundant to the motherboard's current limiting resistors.

 

Maybe I'm still missing something.

 

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16 minutes ago, bfollowell said:

Maybe I'm still missing something.

No, you are right. I missed/forgot that particular board that adds another bunch of resistors. As you say, redundant. And it even slightly decreases the response time ;)

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I think I'm going to try this. Trimming off the end of my mylar would be an easy quick fix, and I may do it, but this would be a relatively cheap and easy permanent fix.

 

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Well, I've not had a lot of luck so far; no good luck anyway. I've had no luck finding 2.54mm 26-pin FFC cable or connectors from Digi-Key, Mouser, Newark, or any other of the regular electronics supply houses I usually use here in the U.S. I did find cable 6 pieces of 200mm cable from Amazon for like $7, so I'll probably go ahead and order that, but I've had zero luck finding comparable connectors anywhere. Any ideas, preferably from North America?

 

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3 hours ago, bfollowell said:

Well, I've not had a lot of luck so far; no good luck anyway. I've had no luck finding 2.54mm 26-pin FFC cable or connectors from Digi-Key, Mouser, Newark, or any other of the regular electronics supply houses I usually use here in the U.S. I did find cable 6 pieces of 200mm cable from Amazon for like $7, so I'll probably go ahead and order that, but I've had zero luck finding comparable connectors anywhere. Any ideas, preferably from North America?

 

These kind of cables do not use .1" or 2.54mm, but rather .039" or 1mm.  You're wanting something like this Digikey search results:  FFC cables

 

Then you need to determine whether you need top exposure on one side bottom on the other or both.  Then the length. 

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Should you order the cable, feel free to choose even longer than 20cm. There is plenty of room inside Atari. It makes manipulation more comfortable.

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6 hours ago, Dropcheck said:

These kind of cables do not use .1" or 2.54mm, but rather .039" or 1mm.  You're wanting something like this Digikey search results:  FFC cables

 

Then you need to determine whether you need top exposure on one side bottom on the other or both.  Then the length. 

 

OK, thanks. I think I must've been focusing on the wrong spec. So, the PCBs adapt it from 2.54mm down to 1mm, so I need 1mm cables and connectors? Also, I've never used these types of cables or connectors, so I'm not certain what is meant by the exposure and which I should choose. Is this referring to where the bare wires are actually exposed? @archeocomp, I'm not trying to reinvent the wheel here. I just want something relatively simple. Which exposure type did you use?

 

Thanks @Dropcheck and @archeocomp! I really appreciate your guys' help.

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Yes, 1mm cables and connectors. Exposure probably means termination side. Choose both ends the same side, length 30cm / 12inch is OK. Then you can use one type of connector on both sides too. Connectors too are top and bottom contact types. They have the same footprint and solder points, so it does not matter which type you pick.

 

If you want I can make gerbers without resistors for the motherboard connector side, as they are already present on motherboard in 800XL. Or you can use some small resistors if you are ok with unnecessery soldering.

Edited by archeocomp

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30 minutes ago, archeocomp said:

Yes, 1mm cables and connectors. Exposure probably means termination side. Choose both ends the same side, length 30cm / 12inch is OK. Then you can use one type of connector on both sides too. Connectors too are top and bottom contact types. They have the same footprint and solder points, so it does not matter which type you pick.

 

If you want I can make gerbers without resistors for the motherboard connector side, as they are already present on motherboard in 800XL. Or you can use some small resistors if you are ok with unnecessery soldering.

 

Yes, that would be great. I would really appreciate it. I'm not opposed to soldering, but I hate unnecessary work, and all those unnecessary solder points are just more points that could cause trouble.

 

Thank you for offering.

 

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OK, here's the connectors and the cable that I ordered. Now I just need to order the PCBs for both ends after @archeocomp removes the unneeded resistors from the Gerbers file of the motherboard side board. It'll be nice to get my ALPS Type I going again!

 

Thanks guys!

 

 

 

https://www.digikey.com/en/products/detail/molex/0522072660/5170985
https://www.digikey.com/en/products/detail/molex/0152670441/4427307

Edited by bfollowell
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Your DIGIKEY order looks fine. Here is the files. PDF is included for you to print out on paper and check in Atari if it fits. I tried to upload gerbers to OSH and it complains about missing drills and bottom side, but that is OK, there are no drills and bottom side. Upload it yourself and double check please against shared 600XL adapter, to me it looks legit. Do not forget to choose flex PCBs when ordering.

keybAdapter800XL.zip

Edited by archeocomp

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16 hours ago, archeocomp said:

Your DIGIKEY order looks fine. Here is the files. PDF is included for you to print out on paper and check in Atari if it fits. I tried to upload gerbers to OSH and it complains about missing drills and bottom side, but that is OK, there are no drills and bottom side. Upload it yourself and double check please against shared 600XL adapter, to me it looks legit. Do not forget to choose flex PCBs when ordering.

 

 

Thanks for the Gerbers files. It showed up as a tenth of an inch narrower than the original PCB, but I printed out the pdf and compared it to the motherboard slot and it looks perfect.

 

Thank you very much @archeocomp!

 

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Hey @archeocomp, I'm not sure how often you're on the forums, but hopefully you'll see this before too long. I ordered the connectors and the molex cables several months ago, but I've been busy all summer and am just getting around to ordering the PCBs. I'd prefer to use oshpark for both PCBs to save on time and shipping costs. I downloaded the Gerber files for the keyboard side board from pcbway and uploaded them to oshpark, but it says that it has a critical failure because the Gerber doesn't include a board outline. Do you happen to have a Gerber zip with the board outline file included?

 

Thanks.

 

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