PCB replacement membrane for Amiga 500/500+ keyboards - work in progress

[RetroBox]

Hi.

I found EAB recently and like to share with you my recent project - AmiKey - a repleacement keyboard membrane for Amiga 500 and 500+ in form of PCB.

I already got the first prototypes but they are not functional yet (more info on links below). I'm currently fixing little issues in my design and hope to get next batch of prototypes in a week or two.

If you have any questions or suggestion then this thread is a good place for it :-)

I'll be posting updates as things goes.

[RetroBox]

Order placed for revision B! PCBs should arrive in about two weeks. I should have them tested in first two weeks of october. I hope those are last prototypes and next revision will be production one :-)

[solarmon]

Nice work! Always great to see another option for Amiga keyboards!

What is really needed is a solution for the Samsung dual membrane keyboards.

[wiz12]

Are these the same replacement membranes (similar look) which Sordan sell on ebay?

[RetroBox]

Originally Posted by solarmon

Nice work! Always great to see another option for Amiga keyboards!

What is really needed is a solution for the Samsung dual membrane keyboards.

Thanks! I never had a Samsung keyboard in any Amiga 500 so I'm not sure what membrane types they have. If they're dual membranes (with separator inside) then I don't think they can be reworked in form of PCBs. If ithey are single membranes just with two connectors instead of one then its a simple modification of PCB layout (changing connectors and redoing part of tracks).

Originally Posted by wiz12

Are these the same replacement membranes (similar look) which Sordan sell on ebay?

No. These are different PCBs. The ones on Sordan fits both A500 and A1200. My PCBs will fit only A500/A500+ for now. I plan to add FFC connector for A1200 in future (after getting my A1200 up and running and getting spare A1200 keyboard to work on). I think its obvious they look similar, they fit the same keyboards.

However I have to admit that idea to draw my own version of PCB to cut costs on A500 keyboard repairs came to me after searching online for cheapest membrane replacaments. Sordan popped out in the search results with its PCBs along with different A500 PCBs (by kipper2k if I remember correctly).

So perhaps I'm reinventing the wheel but the prices of replacement membranes (both flex and PCB ones) are simply nowhere near the cost of PCBs ordered directly. The cost of single 0.6mm PCB with gold plating should be about 10-12 euros including shipping and tax/customs when ordering 5-10 pieces. The 0.4mm ones would rise the cost to about 15-17 euros a piece. I use JLCPCB for my orders.

[amiman99]

The same membrane from A500 can be used in A3000 keyboard and probably A4000 too.
I have A3000 keyboard that uses the same membrane, I'm actually waiting to get PCB replacement for it. P/N A-500(E)56 A619A

[RetroBox]

Originally Posted by amiman99

The same membrane from A500 can be used in A3000 keyboard and probably A4000 too.
I have A3000 keyboard that uses the same membrane, I'm actually waiting to get PCB replacement for it. P/N A-500(E)56 A619A

I didn't know that A3000 used same membranes. I've used Mitsumi A-500(E)56 A619A and A619B to draw my PCB. I will change description on PCB so it will clearly say which membranes it replaces. Thanks.

[solarmon]

Originally Posted by RetroBox

Thanks! I never had a Samsung keyboard in any Amiga 500 so I'm not sure what membrane types they have. If they're dual membranes (with separator inside) then I don't think they can be reworked in form of PCBs. If ithey are single membranes just with two connectors instead of one then its a simple modification of PCB layout (changing connectors and redoing part of tracks).

Yes, the Samsung ones have separate membranes with separate connectors. I just wished somebody made replacement membranes for them.

[Jope]

Originally Posted by RetroBox

I didn't know that A3000 used same membranes. I've used Mitsumi A-500(E)56 A619A and A619B to draw my PCB. I will change description on PCB so it will clearly say which membranes it replaces. Thanks.

Really late ones had.

I've never owned a membrane big box keyboard as far as I know, only ones with a large PCB. :-)

[Rissy]

Originally Posted by solarmon

Yes, the Samsung ones have separate membranes with separate connectors. I just wished somebody made replacement membranes for them.

Count me as number 2 for this. I now have two Samsung keyboards in my possession. For one of them, 1 key doesn't work. For the other, not a single key works!? Not sure what's going on. Whether it's a membrane issue on both or not....?

[RetroBox]

AmiKey is not a dead project

I had to focus on my family for over a year soon after testing AmiKey revision B prototypes and wasn't able to finish revision C until earlier this year.

Lately I decided to make AmiKey available to anyone for private, non-commercial use so if you need a PCB membrane for your Amiga 500/500+ or 1200 feel free to visit project home page and download the gerbers so you can place an order at your favourite PCB manufacturer.

https://8bit.re/amikey/

If there are some question for which the above project page has no answer I'll be happy to answer them here, just let me know.

[RetroBox]

FYI: I've just released revision D of AmiKey. Besides small routing fixes and PCB cleanup it brings two new variants: A500 which fits only Amiga 500/500+ and A1200 which fits only Amiga 1200 for all those Amiga users who don't want additional connector on their keyboard membrane (especially A500 connector sticking out of your A1200 keyboard ).

[solarmon]

@Retrobox

Nice work indeed!

I'm working on my own keyboard PCB. I'm finding that with 0.6mm PCB thickness the connector is not reliable enough - because it cannot bend/flex, since the keyboard connector actually sits a bit higher. I will now be trying 0.4mm PCB thickness - but this costs more to manufacture - and see if it is able to flex/bend enough to sit in the connector without issue.

I also found that the 0.6mm PCB thickness is OK for the connector, if you have a base PCB (or some other material) underneath it to raise the keyboard PCB so that it doesn't bend when sitting in the connector. However, creating a PCB base would just be as costly as the keyboard PCB itself, unless some other cheaper material and manufacturing method is found (i.e. some laser cutting service that cuts thin sheet plastic using gerber design files).

Cheers!

[RetroBox]

JLCPCB now also manufactures flex PCBs with thickness 0.11, 0.12, 0.2 mm and ENIG finish. Haven't tried it yet, but cost is similar to 0.4mm PCB. For me 0.6mm was too thick as well for same reason and beacue metal backplate required a bit longer screws.

[RetroBox]

FYI: Revision E was released. All three versions were rerouted to minimize number of tracks on the bottom side which has contact with metal keyboard backplate. Also, missing additional key pads for left shift and return were added in A1200 version.

Unfortunately gerbers are no longer available for download thanks to some "smart" people who have manufactured AmiKey without silkscreen (to get rid of author and license info) and are selling them for profit. You can order directly from PCBWay instead.

Be aware that I have not manufactured revision E yet and since the boards were almost completly rerouted there may be some flaws there despite the fact that they pass all DRC tests in KiCad.

[solarmon]

Originally Posted by RetroBox

Unfortunately gerbers are no longer available for download thanks to some "smart" people who have manufactured AmiKey without silkscreen (to get rid of author and license info) and are selling them for profit. You can order directly from PCBWay instead.

This is why I'm a bit reluctant to release the KiCAD design files for my own keyboard PCB membrane - I'm fine with users in the community making and selling them, but don't like the idea of a commercial supplier making and selling them.