Hi fans -
so far - all these years - I have been building Apple-1 keyboard cables by hand, on one end with a DIL-16 press-fit (IDC) header, or, in case of my keyboard emulator cables, a DB-25, and on the other end (the Apple-1 side) there was a hand wired contraption involving yet another DIL-16 pin header, and a diode or a NPN transistor. All these solutions worked but looked ugly. None of the other PCB solutions I ever saw looked much better - they just were too large in size, and some of these PCBs even had the CLR SCREEN button on them, which IMHO is awkward. They should have figured out how to do the CLR SCREEN from a key on whatever keyboard is attached. I know this can be tricky - long cables conspire against doing this, because the CLR SCREEN is a "live" signal within the Apple-1 cursor state machine, and worse, it's a wonky diode / resistor / switch OR gate, so with enough capacitive load or crosstalk from a longer keyboard cable it just won't work and may sabotage the screen output. This is why I use those diodes or transistors to isolate the switch from the cursor state machine until the switch is pressed.
I always wanted a nicer, smaller solution, so here it is:
This may be the smallest A2-A1 keyboard adapter PCB in the world. No sure, though - prove me wrong by linking to a smaller prior art one in a comment you write. Here is the PCB before the final assembly step:
and the bottom side with the hidden-from-sight SMD NPN transistor (yellow arrow pointing to it) is here:
This adapter allows the use of a flat band cable with DIL-16 headers on both ends:
... and the other end plugs into a slightly modified Apple II keyboard encoder card, or any keyboard replacement or substitute ever made for the Apple II. Since the pinout of the keyboard connector on the Apple-1 and the Apple II motherboards is much different, the little PCB shown above does all the signal permutations in the smallest possible space.
The mods to the Apple II keyboard encoder (the 25 pin encoder for the dual PCB keyboard version used in the later Apple II) are small, two traces are cut, and three wires and a resistor are added. This little mod changes the REPT key to be CLR SCREEN and has no other effect (other than losing the key repeat function). So this keyboard with the same flat band cable, less the A2-A1 adapter, can still be used for the Apple II.
I find this dual use solution very convenient because functional original Apple II keyboards are hard to find nowadays, nearly half a century later. Most have one or more bad key switches, and replacing them can be difficult, and futile, because the replacement switches harvested from another keyboard are of the same old age. It's not only the switch contacts which go bad, but the key stems also became more brittle after half a century. It is one thing to preserve an Apple II as a static display in a museum ("static" in this context meaning never to be powered up / used) but it's another (much more difficult) thing to bring it back to life to actually be used. Building a new keyboard with new key switches is perhaps the best option, see here:
https://www.applefritter.com/content/uncle-bernies-yaak-yet-another-apple-keyboard
Note that YAAK has two versions, depending on which components are put into the same PCB, one version has an on-board scanner which needs a proprietary encoder (I did not finish its design yet, but I do have a fully functional "C" implementation waiting to be converted into PIC assembly code, and only after it was proven to fit, I can design the PCB for it). But this is not the YAAK version proposed here in this thread.
Instead, you may use the YAAK version with no on-board scanner and just the 25 pin Hirose connector to plug in either an original 25 pin Apple keyboard encoder, or one of the various substitutes which were developed over the past decades (and appeared and disappeared). My take on this is that for each hopeless case of a rotten Apple II keyboard of the dual PCB type, there is a leftover encoder card which most likely still works, or can be brought back to life by replacing the poor quality IC sockets and maybe the pin header row (if corroded), too. All these components are still available and unless the keyboard encoder LSI is dead, it's an easy and cheap repair. If the LSI, the unobtainium AY-5-3600-931, Apple part #331-0931-B, is dead, be aware you can't just use any other salvaged AY-5-3600, because this keyboard controller is mask programmed, and you need the version made for the Apple II keyboard matrix. So far, I never had a bad Apple keyboard encoder card with a dead LSI, and it seems if the DIL-16 cable is plugged in turned 180 degrees, only a TTL would die, but not the LSI - happened even to me to plug in the cable in the wrong way - so I had to replace the TTLs (2 x 74LS00 and 1 x 74LS04) occasionally, and I never had to replace the LSI. Maybe I just was lucky - so don't try this stunt yourself. But even for cases with a dead LSI, there is hope, because some people in the Apple II scene have made substitutes based on a small PCB with 40 pin DIL header, and a modern SMD microcontroller on it, and this is a plug-in substitute for the unobtainable Apple part. Alas, these substitutes come and go - after their designer(s) have sold off their excess inventory of empty PCBs, or their small production runs, they may be gone. This is how the economics of our hobby conspire against us - it makes no sense for an individual to order a qty one PCB, and so more have to be bought, the excess sold off to other hobbyists, and when these PCBs are gone, they are gone.
This said, I do have a small excess of these A2-A1 adapter PCBs. Price is $2 (plus postage) for each PCB kit. These are my own costs, no profit, and offer is valid only as long as supply lasts. The kit includes a raw PCB (you need to file off the mouse bites) and the 16 special (nowadays unobtainium) golden pins, and the SMD NPN, but no other parts, so no IC sockets and no flat band cable included. Note it makes no sense to ship to any place outside of the USA because the postage to foreign countries would exceed the value of these components by an order of magnitude. Still, if you live in the EU, you may get one in a few months from now, shipped locally.
If you are interested in getting one of the A2-A1 adapter kits, please send me a PM. Use the "send PM" button on the left hand side of this post - it will appear only when you are logged in.
Provided if there is enough interest, I will make a writeup on how to build this thing and how to modify an Apple II keyboard encoder.
- Uncle Bernie
Hi Bernie,
Some time ago I also made something like this, see the thread here.
But I have to agree with you, think this one is the smallest out there!
Keep up the good work, regards from Holland,
Bobby
Perhaps I agree that this model is really the most compact, so much so that there is no place to write "Uncle Bernie" :-)
What's the point of selling it for 2$, it's not even a peanut business anymore, but some kind of mouse business? Wouldn't it be easier to just make this project open source and post the gerberas here on Applefritter? I think a lot of guys would thank you for that.
In post #3, "Macintosh_nik" asked:
" What's the point of selling it for 2$, it's not even a peanut business anymore, but some kind of mouse business? Wouldn't it be easier to just make this project open source and post the gerbers here on Applefritter ? "
Uncle Bernie answers:
It's not meant to be a "business" - there ain't no viable "business" in the Apple-1 scene, despite there are a few commercial (and quasi-commercial) players who try to sell their Apple-1 related wares at a profit. As far as I'm concerned, I don't seek any "profit" and never had one with all these Apple-1 activities of mine. Despite of all the IC kits sold I'm still in the hole by a few grand (1000's of US$) but I do have about fifteen Apple-1 clones laying around, and these are all what I can show for all my Apple-1 related efforts, activities and money and time invested, over the past 6 years ! Never mind that lots of people who actually work for a living (I never had to do this after I turned age 30) and toil as a slave / serf for greedy corporations for 40 years until retirement also have nothing to show for it. They don't even own the shack they live in because they could not afford a house. So they still pay rent to greedy landlords. This is why I label them as "slaves / serfs". This is capitalism - with free range serfs. Communism is worse - only the inner party members get rich. I would prefer Randianism (actually, the correct name is "Objectivism" but this word confuses anyone who did not read "Atlas Shrugged"), which in a nutshell is free enterprise, no government red tape, no coercion, no exploitation, you keep what you work for, and your pursuit of happiness is free of obstructions tossed into your way by bureaucrats / desk criminals, but if you are lazy, and don't work, you starve. However, a Randian state does not exist anywhere in the world. And I doubt it might work as advertised ("Galt's Gulch"). Capitalism, Communism, and any form of Parasitism aka "Welfare State" don't work either. But have been tried out and have been proven to fail. Just look around you and see. There is the proof.
This said, I have a certain mindset about any kind of deal, and I think if I ask for a price which just covers my own costs for the parts I offer, is fair. Sure, at $2 I could give these kits away for free, but would you be willing to pay at least the postage ?
There is also a psychological factor in it. If I gave you a candy bar worth 50 cents for free, you might throw it away. But if I make you pay 50 cents for it, you will eat it and not throw it away.
Same with electronic components. I used to give some away to people who were interested (or so they pretended) to build one of my designs, just to find out they never would build anything and just stash these parts into a drawer to be forgotten. This was in the 1980s and early 1990s. I learned my lesson and never gave parts away for free anymore. People tend to consider freebies to be worthless and let them go to waste. Same psychology as with the 50 cents candy bar.
And, for the particular case of the A2-A1 adapter, I think it is simply not viable for individuals to take Gerbers and make these A2-A1 adaper PCBs. PCB manufacturers have minimum PCB sizes and socket costs conspiring against qty 1 production runs. To reach the minimum PCB size with smaller PCBs, you need to group them into "gangs" of several separatable units. This is where the "mouse bites" I mentioned in my first post come in: these structures allow a CNC milling process to almost separate the units but these are still held together with the "mouse bites". The whole PCB is still held together by a frame including fiducials and alignment holes for the SMD assembly robot. After all the SMD parts have been placed and reflow soldered, the frame is cut away with coarse cutters and the "mouse bite" tabs are broken off. This yields a small, completed PCB with a nice smooth outline except for the places where the "mouse bite" was. These have nasty glass fibers sticking out and these must be removed with a file and / or sandpaper.
The issue with the Gerbers I have right now is that it's a multi project PCB comprising many sub-projects and it took me four years to fill it to a point where I had collected enough sub-projects to reach the required total size. Here it is:
Adapter_set.jpg
I don't think that anyone out there would want to waste all that money for the whole thing just to get one A2-A1 adapter PCB out of it (yellow arrow).
And no, I'm not willing to make another layout with only A2-A1 adapters ... there would be maybe 20 of them on one of these PCBs and since ordering qty 1 is far too expensive, you have to order at least 5 of them (if you are using JLCPCB) and so you end up with about 100 such A2-A1 adapter PCBs. What do you intend to do with the excess ? Sell them for $2 on Ebay ? Note that there are less than 1000 Apple-1 in the world and most do already have a keyboard solution. So I guess that not more than about a dozen people worldwide would be interested in acquiring / building one of these adapters because they have an ugly and less desirable solution right now.
And then there is the problem how to source the special pins, which come on carriers, and are not cheap:
DIP_Carrier.JPG
Note that this example is the best offer I could find, but its pins have a diameter which is already far too large for being plugged into regular IC sockets (the Apple-1 keyboard connector) without overstressing the contact springs. I happen to have a stash of similar carriers with a smaller pin diameter which are just right. I use them for all my SMD adapters which go into DIL sockets. (The large TQFP adapters seen in the above photo of course don't use DIL sockets and don't use these special pins, they use regular square pin rows which go into suitable sockets built from dual and single row strips)
So, now you know all the (good) reasons why I offer these A2-A1 adapter kits for $2 plus postage. I can furnish maybe 20 of them or so. Not more. Not less. When they are gone, they are gone. And I don't expect to sell all of them - I think most of them I will just throw into the trash bin. It's not about profit, I just wanted to give those Apple-1 builders who want a nice, good-looking solution a chance to get one for cheap.
So get yours now, as long as you can !
- Uncle Bernie