I have a Amiga 1200 that i put in a pc tower(about 1994). I programmed a microcontroller to interface to a pc keyboard. I remember i had to cut two wires on the A1200 mainboard between the keyboard controller and the rest off the machine to patch in my controller.
A more elegant solution would probably be to trigger the different behaviour by the cable you connect to the keyboard. You probably would need an 8-pin din connector for this to carry all the 7 signals needed for the Amiga 500 plus the switching signal that goes to the transistor. For big box Amigas still only 4 signals need to be connected.
As only the A500 needs the reset line, and as the A500 provides the power and activity lights, could you have a relay connected to the power LED line, so when the power LED is active it enables the reset pin, and when it isn't, it doesn't?
@@copperdragon9286I was under the impression it could be either low, or high, but not off. Alternatively, it could latch, so if the power light pin has any power at all, it latches on and uses the +5v line to keep itself on.
Being switchable is certainly handy, and it's akin to how PC keyboards had switches to go between XT and AT standards, and, I didn't know a 500 keyboard could be converted to work in a 1200, so that's pretty cool too... :D
@@JanBeta Trawling forums trying to find info is quite challenging at times, especially as google give such vague results when you need something specific, heck, at the moment I'm trying to find the IBM version(s) of the software for an Okimate 20 printer with the RS232C interface, but all I get is the Commodore IEC one, could be one of them things lost to time, given they weren't that popular a printer outside of the C64... :\
Nice mod :) My A500 keyboard cable is the type with one missing wire (Scandinavian keyboard). Used it yesterday after staying unused almost 1,5 years but it worked just fine as always :)
The extra wire is a bit odd on these keyboards, especially considering Commodore's usual cost-cutting. But I guess they used pre-configured connectors for most of the keyboards that just had all the wires fitted from factory. :D
Very useful and entertaining. I doubt I’ll ever own a big box Amiga as it seems a difficult task outside the US, but your video was informative nonetheless. Much appreciated.
I actually did use a A500 keyboard back in the days, on a A1200 board not by replacing the menbrane. but by soldering the i think about two keyboard data and keyboard clock lines to the responsable chip on the a1200 board. actually It was an A500 keyboard with all key ripped of an CDTV keyboard to make it a black edition 😞 thats how it was done 30 plus years ago, sorry. and indeed it needed a reset button also soldered straight on the a1200 mobo.
the Amiga's keyboard protocol never changed between all of the machines - the main thing the 600 and 1200 did was move the keyboard controller onto the main PCB. AS you say, you can feed the data and clock lines straight to the CIA and it will work. This is also how I modified my own A1200 to use an A2000 keyboard. A small circuit can be made which produces RESET as well
@jaycee1980 : yep! As I remember, INFINITY towers or/and EAGLE towers also had a little circuit in a casing for the A1200 to use an 2000/4000 keyboard (not for an A1200 keyboard in particular) . funfact: i also fitted a KeyrahV2 togeather with an A1200 KB in an old A2000 keyboard KB casing to make it USB for my emulator setups.(funny, two DB9 connectors on the back of an A2000 KB/USB)
Great video. I wouldn't recommend leaving the transistor's base floating, though. It might act-up because a BJT usually has a relatively high gain, and letting the base float could make the system unstable. Use a SPDT switch instead, with the "big box" mode position connected to ground through a 100 ohms resistor. The A-A-CTRL key combo is actually resetting the keyboard itself, that's why it won't send the scan-codes down the interface. Just my two cents
I really must look at replacing the A500 keyboard PCB with a modern microcontroller.. it would also be trivial to add a mode which would make it suitable for external keyboard use by pulling KCLK low for reset, rather than an external reset signal!
I'm working on a video about an A2000 keyboard that uses a Teensy with a modified regular PC keyboard firmware to do that. Should be relatively trivial to modify to work on an A500, too. It's this project: github.com/grahamshaw1972/a2000Serotina
@@JanBeta Yeah ive seen a few projects, but always with things like that or the Pi Pico. Massive overkill for whats needed... I'll keep thinking about using an AVR to do it :)
That's a very nice modification and it gives the Amiga community another keyboard solution option. I know how frustrating Amiga Keyboards can be especially for those who only have one Amiga. I own several Amiga's and the ones I use most are in a server rack connected to a KVM Switch so I now have a lifetime supply of Amiga Keyboards to use on my other Amiga's that are still in their original cases. I do have an A500 Keyboard in a Checkmate case that I used for a short period of time so I might do your modification. I do already have working Big Box Amiga Keyboards so if I ever pull a Big Box Amiga or sell one, I have the keyboards to go with them. No point in selling any spare keyboard because I recall keyboard issues in the past when I did not have spares to put to use.
I once had an A2000 keyboard that I tried to take apart for cleaning. Normally I do this by pulling off all the key caps, taking out all the plungers and washing all the plastic parts. However, after pulling off the first keycap, I decided not to go any further. Rather than having a plunger under the key, there was a small diameter spring, and two metal contacts sticking up. A piece on the underside of the keycap went between the contacts, so that when the key was up, the contacts were held apart, and when the key was pushed down, they would come together. I decided to put the keycap back on to see how hard it would be, and it was a royal pain in the ass. Since the contacts went up inside the keycap, it was extremely difficult to hold them apart while trying to put the keycap into place. Once I finally got it back on, I decided that doing that to the entire keyboard was more trouble than it was worth.
Nice. I never had to do this, but a cool little DYI adapter. Thanks again brother for another cool video. I have the same pen from Marvin over at the Retro 8Bit Shop. 👍👍😎😎
I rediscovered my A3000 keyboard a few days ago, thanks for the AT to PS2 tip. I had forgotten how I used to connect it to my CD32 which has the A4000 type connector.
Nice. I used to use an A2000 keyboard on my A500! I added a din connector at the back. Reset doesn't work (as per your video) so I wrote a utility that installs a reset handler that reboots the machine on Ctrl-A-A. This only works while AmigaOS is running so I also added a reset button on the back. I have no idea how I did any of this! The A500 is long lost and so is the reset software.
Yeah, they are not very available at the moment unfortunately. But I think there's some more options in the works (A1200net mentioned something about a mechanical keyboard some time ago, for example).
This reminds me that I should see if I could fix my A4k keyboard. It started acting up in the early 2000's so I got a A2k keyboard to replace it. The latter still works but I actually never opened up the former to see what was wrong with it.
@@JanBeta Might just need a good cleaning as well. It's just some keys that don't work on it. I guess I was just lazy back then and since I got the brand new A2k keyboard fairly cheap I never bothered.
I had the A2000 for a few weeks with the AT bridgeboard when released. The AT board was too unstable for my coursework, so had to buy a PC in the end. Have A500+ and A1200 now. Would love one of the big box machines again.
I would love a proper keyboard for my 2000 but they are far too expensive and that's if you're lucky to find one!.. I currently use a DIY PS2/USB keyboard adapter.. I might do this mod to an A500 keyboard for it one day, but can't justify the £65 for the bare metal checkmate case. Maybe I'll try the 3d printed one :)
I am quite lucky there - I owned an A2000 Braunschweig Edition and still have the original Keyboard with Cherry Keys. Still the best Amiga keyboard ever, with double shot keycaps (exept for the Amiga keys, they are pad printed). I actually used it with an adapter on my A4000 later. It founded my adiction to mechanical keyboards, privatly I only use mechanical keyboards since then. While I nowerdays prefer clicky keys, I never got used to membrane keyboards. For 3d printing a keyboard case, I still think about building a big size 3d printer (500 or 600 mm square). I realy prefer the top surface to be one piece instead of two. Actually there are open source PCBs to do your own mechanical Amiga keyboard. However, getting the keycaps is quite a problem. The only way without printing the keycaps yourself might be to hollow out the inside of original keycaps (or the black ones from A1200.net) and glue a self printed adapter for cherry like keycaps inside.
Agreed. Ebay prices for big box Amiga keyboards are way too high. I'd love to get an A2000 but most of the time they don't come with a keyboard, so at least this video is another option that works just as well and is a lot cheaper.
@@LeftoverBeefcake The big problem with A2000 keyboards imho is you pay a lot just for being Retro, but what you get practicly is the same techniqe you have in a $10 keyboard. So paying $170 is simply insane. In Germany this is a bit different, as the A2000 first was developed here and also back in the days Cherry was a German manufacurer. While internationaly A2000 cherry keyboards are sort of a myth (never saw one), in Germany they are much more common. However, many Amiga lovers seem not aware about the differeces between the A2000 BS-Editition keybord made by Cherry and the "normal" A2000 keyboard. Actually I got a second Cherry one 3 years ago for about $170 on eBay. For Cherry PC keyboards you still pay about $70, as they are made with individuell keys. For double-shot keycaps (you do not get a new cherry keyboard with double-shot keycaps nowerdays) you can get them for about $30 used (old G81 keyboard and transfer the keycaps). So if you could get an A2000 BS-Editition keyboard, the hardware itself is worth about $100. You pay $75 for being "retro", having the original Amiga layout and need no adapter. Also you can retrobright the keycaps (exept the two Amiga keys) without getting letter-soup. Such a keyboard last an eternity. So imho its worth it. However, for normal Amiga keyboards such a price is insane. Converting an A500 keyboard imho is definitly the better alternative than paying insane prices for pretty standard keyboards.
Hi there. I am in the process of converting an A500 keyboard into a keyboard for my A4000TX and i am using a black checkmate case to match my black tower. Thanks for this video which has been very handy. About the reset signal, if i understood well, i can just remove completely the Q1 transistor without soldering anything else in its place and keep going?
Would I be able to use the USB C as a input to the Arduino to the output as PS2 connection to the Amiga 4000. Which I believe is the opposite of what your video is. Thank You
Do u think the high current costs especially in Germany could threaten the Retro community?While one can use emulations like WINUAE or X 64. As much as i like old Computers.Een bought a Monitor consuming 17 W my old 50W for me is important.
The cost exploded around the world as far as I can see. I think it won't stop people from embracing the retro hobby anytime soon though. More people being interested in that stuff unfortunately means more demand and higher prices. There's still a couple of systems that are relatively inexpensive to get into (like the Megadrive for example) but most favorites from back in the day got really costly. Not much we can do about that I guess. :/
