Here is the link to the preorder page at AOTL

And here is the link to the EAB forum thread

So what's new ?

A couple of months ago I was going to use one of my A500's and for some strange reason it decided not  to play. No light on the Power LED and the floppy drive light was also dead, after a quick swap of the A500 KB controller I was back in business. It was at this point that I was thinking that spare parts for these keyboards are fading fast. I also noticed that some of the keys pressed on the keyboard were very flaky to say the least and some kind soul donated a new cloned A500 keyboard membrane to me.  A new membrane is nice but what about the broken A500 controller board I now had sitting around, I decided to see if there is a way to create an overall fix. I realised that the A500 and A1200 membranes are swappable and decided to reverse engineer the original membranes to make sure that my layout would be 100%.

 After a few days of changes, checking, rechecking and then staring at the monitor for hours I was finally happy that the layout looked good, the first version I wanted to check would be my redo of the schematic on a 0.4mm PCB so it would replace the original membrane of an A500. One thing I noticed is that when you do continuity checks of a membrane the resistance can vary from 30 to 300 ohms which surely must cause some sort of lag and indecision by the controller. Once replaced with a PCB the line resistance is now less than 1 ohm. Lining up the membranes holes and contacts was a royal PITA and after using the "measure 100 times, cut once" rule I finally got a workable image.

 Off to china the design went and I received 10 x A500 PCB membranes 10 days later, very nice looking, but do they work?  The first design was designed with a edge connector that plugs into an A500 KB controller. This version was simply to test my tracing abilities and to my pleasant surprise, all key presses responded correctly to the mapping. There was no controller circuit on this board, that was next...

First PCB Membrane, a500 only... no onboard controller

this first version works on  only1 type of a500 keyboard due to the different designs (damn them!)


 Ok, so now I have the working PCB membrane it was time to update it with its own controller and get rid of the archaic original one. Thanks to Mike Stirling he chose a pic 18fxxx to replace the MCU and has offered to do the coding so now it is a case of mapping all the address lines, control functions and other required signals to the PIC. after a few days work (or more lol) all was done and in the coming weeks it was tweaked and retweaked to where it is now.. We even have USB on it :) but more on that later. So what I wanted to do now was to make a "universal" A500/A1200 PCB membrane  that can be used in either/or. The A1200 obviously doesn't need a KB controller as it has its own on the motherboard so I just simply need to connect the KB to the motherboard connector with no extra circuitry on the membrane. The A500 will have the PIC chip and connect to the motherboard via a 8 pin header (there will be no PIC on the a1200 version). Off to China we go again...

 10 days later I get the boards and they look great, the boards can supposedly work on both computers and these are still membrane PCBs that will sit inside the KB casing. First thing to try is to hook up the A1200 cable I designed from the KB to the motherboard and try. YES!! all looks good, adding the new stuff to the PCB membrane hasn't killed it, the board now needs the code for the A500 to come to life.

New A500/A1200 PCB membrane connected to an A1200

Verifying the KB output is good. Using Systest by Keir Fraser, an awesome utility

This board will work on all A500/A1200  keyboards. The A500 version will have the built in LEDs on the PCB. The MX version will have the A1200 cable located underneath and the A500 cable will be parallel to the motherboard connector to reduce the length of cables required


 Next up, the A600, similar process again, mapped it from scratch and for the most part it worked, I thought there was only 1 version of the green plastic membrane, Wrong! there are 2 and the enter key was in wrong place for some keyboards so I was a little disappointed. Now it gets interesting, as I am testing the A600 key presses I found a lot of the rubber contacts are very bad and not reliable at all. These are not available any more and it is time to replace, a lot of these repair kits are garbage or just too much fiddling about.  There has to be a better solution...


A600 PCB membrane (works for both green  and blue Keyboards)

 This board replaces the metal plate underneath the A600 keyboard as I used a thicker PCB which is strong enough to withstand the keyboard slappers. The A600 membranes and upcoming will have an awesome Power LED addon available so you can chuck the crappy original one :)

 Enter Cherry MX, why try to keep alive and spend money on an old unreliable keyboard when hopefully it can be replaced with a much more reliable, responsive keyboard which can be easily fixed and parts are abundant.  There are lots of places where you can buy key caps in multiple colours, sizes and at decent prices so lets take advantage. Fortunately there are only a few differences between the A500 and A1200 cases so using a universal designed Cherry MX board in either shouldn't be an issue.  (There will be slight differences between the 2 of them to allow for the LED board for the A1200 which is a separate screw on board)

 The design of the A500/A1200 Cherry MX keyboard is relatively simple, it is in 2 main parts, the upper plate is where the MX switches are pushed down and lock into place, the lower plate is where the switches are actually soldered to.  Due to the fact that Commodore were pretty well proprietry in some of their designs the majority of keys are the wrong size when compared to their PC equivalents, with a massive spacebar and bigger Function keys etc. So now the task is to maintain the Amiga key layout and make it fit into the hole of the Amiga upper cases. A little bit tricky but wasn't all that bad and we have come up with a slightly modified layout that needed an extra couple of blanks and a smaller spacebar. We have put together a shopping list and can purchase all the different sizes we need without having to go to fabrication.

 So what about the USB ? - The PIC chip on the a500 MX keyboard (and membrane version) should be able to connect to a Pi, arduino etc and allow you to use the Amiga keyboard as an input to your device :)

 So where are we at now (12th Oct 2018 ...

- The A500 membrane version needs the PIC code finalised.

- The A1200 membrane version works

- The A1200 Cherry MX version is just going through final checks

- The A500 Cherry MX version is awaiting code also

- The A600 membrane is complete (3 versions in 1).

- The A600 Cherry MX version requires a bit of work (about 6 more weeks mabbe).

Here is some pictures of the proposed A600 MX layout

I have found a supplier that provides the keys in original sizes so depending on the prices i will either change this one or design  an alternate version, we'll see.


Here are some pictures of the (almost) completed A500/A1200 Cherry MX Keyboard



 Here is a video of the a500/a1200 Keyboard set up in an a1200.  I am still waiting for some of the keys to arrive to finish it off so keep that in mind.



So, what's in the future? there is no reason why we can't replace the Big Box Amiga keyboards now with Amiga lookalike visuals, it just needs to be designed, It is also easy to add background lighting to these keyboards now, I designed the option for people to add bright LEDs to each switch (too much work for me ) and power it from either the 12v rail or an external supply, ( Don't use the 5v rail) you can buy cheap LED strips on ebay and easily add them to the keyboard if you want and there are quite a few options that can be explored.

 I really don't have any intentions of selling these myself as there is not enough time to do all the things I want to do as it is, i will make a few but for the most part Aaron at AOTL will sell them and also there will be someone in the UK that will sell them. This will reduce the "shipping costs are too high" complaints. As for the price, it all depends on Pre orders and expected demand, these are big bulky boards and shipping using faster means is pretty expensive so we will need to base customer cost on our expenditure and my initial dev costs.  Availability of these is not that far away, the basic boards take ~ 10 - 12 days for me to get and the switches can be sourced from a US reseller (faster and more expensive) or ebay (slower and cheaper). The list for key caps purchases we will see what the discounts for bulk orders would be from my US supplier, The options for many colours (which are available) make it a more complicated process). There are over 200 colours available so you can see why it could be tricky to do a bulk order.

Many thanks to Keith Dumoulin for his ideas/input and sending me bits and pieces to help move this project along faster. I hate it when a project drags its feet or ends up as vapourware so i normally keep my mouth shut until i am almost done :) Thanks also to Solidcore and Indigolemon (and Mike again) for their help and direction in getting this project done


*** Design considerations ***

 I have designed these to have the same footprint as the original Amiga keyboards but they are a bit deeper than some A1200 keyboards. Another thing I found is that the expansion slot rail on the A1200 is very close to the bottom of the MX keyboard. For those developers who are planning to create boards that sit in the expansion slot please try to keep the height on the front portion of their boards as low as possible to try to allow both to coexist. For those people who have expansion boards on top of their A500/a600 CPUs I can design a new low profile adapter if needed. I think most if not all A500 plug on adapters will fit as the height clearance is very similar, I don't have all of these addons to test. I am hoping to make the A500 and A1200 physically identical which will reduce costs, at the moment they are identical and the issue is the A1200 LED connector, it sits low in the upper case and causes a little flexing ( and not to mention a possible short ). I think i can fix this with a couple of strategic holes so that it will pass through without interfering with the A500 LEDs.

 If anyone can think of a nice option/upgrade then send me an email so I can give it some thought. I am thinking of adding a few jumpers to the board, a soft reset jumper, and an option to put the PIC chip on both the a500/a1200 boards and find a way to disable it when used on an A1200 so people have the option to swap back and forth etc.


*** Conclusion ***

 With all of the new things now available for the Amiga, I cannot see any reason why people would not want a new keyboard to go with their shiny new cases, accelerators and other new accessories now available for their Amigas. The keyboards could be possible either as a very basic kit or even fully built. The feel and responsiveness of a Cherry MX keyboard is just amazing and the different colours of the switches indicate different characteristics that would appeal to everyone. Thanks for looking :)


oops... almost forgot, many many thanks to the A500 KB controller for breaking, it was the catalyst that started the ball rolling.




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