Category Archives: Apple 1

About Apple 1 computers

Beginning of Year Retro Update

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Mimeo’s

Last weekend, I sold the last of the Mimeo PCBs (Glossy and Matte) that I had in stock. I will make some more matte after I’ve sold some of the first batch of the SCELBIs. I’m down to 4 ACI cards, so I’ll have to do a batch in matte to go with the next batch of Mimeos.

The new movie, “jOBS” will premiere at the Sundance Film festival this month. I’m hoping that the Mimeo PCBs that I sold to the prop house supporting the film, get some screen time and the film is good enough to get some decent reviews.

I still have plans to do a full built up system, but that project will have to wait until I have the SCELBI going. I am sorry that this has been teaser for some folks who have been waiting for it. However, I’m hoping that when I finally get to it, that folks will be impressed with the results, and say that the wait was worth it.

The new run of Datanetics PCBs have been trickling out, maybe a little faster than I expected, given the difficulty of finding components. They have mostly been combined with Mimeo PCB sales. I really wonder how many will get built up. This datanetics PCB batch has been done more of a service to the retro community, as it will be a while before this project breaks even financially.

SCELBI

Quotes from Advanced Circuits on SCELBI boards are about half of what I expected, which is awesome. Nashua Circuits came in as expected, so I guess Advanced will get this business, unless Nashua can do much better (I’ll give them a chance to improve their quotes). Since there is no solder mask, it really shouldn’t make much of a difference who makes them.

Design checks on the base 5 board set is done, and I’m about ready to declare victory on the layout tweaking/matching. The 8H backplane is just about ready, so I’ll probably get a batch of those made to go with the base 5 board 8H set, making it a 6 board set. The backplane has been challenging, as there is no schematic, only a wire list intended for wiring your own chassis. Good images of the top of backplane are non-existant. My orders for the PCBs may go in, as early as this week.

I do have one thing to check on the CPU board. There were at least two versions of the CPU board made, I am replicating a later version. There is a report of an issue with the step function reported SCELBI digest, issue II. Though describing a problem in a later version of the CPU board, this report shows a slightly different design than the one in the version of the schematics/layout that I am replicating. I just need to make sure the schematics that I’ve followed are accurate.

At this writing, estimates for the set of 6 PCBs, with an 8008D thrown in, but no other components, is in the range of 300 dollars. Final price might vary a bit, but I doubt that I could make it go any lower, without making this a one off effort, not to be repeated.

A friend of mine, is looking into doing a reproduction bezel for the front panel of the chassis. He tells me that there are some challenges, as the original was anodized, and most panel manufacturers, these days, do powder coating.

Today, I am going to see if I can generate a BOM (bill of materials) in an excell spreadsheet. Except for the 8008 and memory, I think most of the rest of the electronics components are readily available. I plan on sending the BOM to Unicorn, who have indicated, a while back, that they would do parts kits for this project, like they have for the Mimeo/Apple 1. The relay sockets used for I/O ports in the chassis, are available, but expensive – I’m going to see if I can find a way to get bulk price on those from someone.

The 8B will follow on the heals of the 8H, It uses the same front panel, CPU, DBB, and input boards as the 8H, but requires 4 new boards…

  • new backplane with an extra slot for the memory addressing board. I haven’t investigated in detail, but I hope I can leverage most of the 8H backplane design, making this pretty straightforward
  • new 4K memory module. I already have done the base chip placement for this one
  • PROM board. Cameron Cooper has a draft design, that he says he will let me leverage
  • memory address expansion card – haven’t started

    • All in all, you can see that based on the head start that I have on the 8B boards, this shouldn’t take nearly as long as the 8H has taken, to complete.

    After these are done, there is more SCELBI hardware to be done, a TTY interface, a scope interface and a cassette interface. Power supplies are another potential future project. For now you will need to find a 5 volt and -9 volt supplies. Amperage ratings depend upon the amount of memory and peripherals. According to SCELBI documentation, system with a keyboard, oscilloscope interface, and cassette interface requires the following.

  • 4K memory requires 5 volts at 6 AMPs and -9 volts at 3 AMPs
  • 1K memory requires 5 volts at 3 AMPs and -9 volts at 1 AMP

    • I’m also likely to do an automated front panel controller with a micro-controller, to make loading the memory on the 8H easier. I might be able to reuse my existing PS/2 adapter with a new program in order to accomplish this.

    Brain Board

    Brain Board stock is dwindling, but sales have been very slow, as of late. When the stock runs out, I’ll definitely hold off on making a new run, until demand builds up again.

    SUPERPROTO

    So far, interest has been a bit lighter than expected. However I’ve got wind of a couple of super cool SUPERPROTO based projects, that may just jumpstart sales when the projects are publicly announced. Feedback from folks using the card has been positive, with no unexpected problems or issues reported. I also know of one, well known, Apple II hardware designer that is leveraging parts of the design, which I have published in detail on the SUPERPROTO Wiki, for his next efforts. Even though, I get no financial reward from this leveraging, it is gratifying to know that my efforts are of use to others.

    Apple II rev 0

    A rerun of these PCBs is also in the cards, though I want to make a few tweaks, so it will also come after the SCELBI and probably the fully built Mimeo.

    That is all the retro stuff that I can think of, for now – Happy New Year

    image of “prototype” Apple 1

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    Until I saw this image, I was under the impression that there were essentially three types of Apple 1s.

  • Woz’s hand wired prototype – there may be more than 1 of these
  • Production boards without NTI logo
  • Production boards with NTI logo

    • Now there is photographic evidence of a possible preproduction board with several differences from known production units.

    http://techland.time.com/2012/11/22/behold-some-of-the-first-apple-computer-photos-ever/

    This unit uses the large orange caps like Woz’s hand wired prototype. In additional to that, upon close examination, this board’s layout appears to differ somewhat from the known production boards.

    Mimeo 1.01 images now on Mimeo Webpages

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    I have now updated a couple of images on my Mimeo Web pages with images of the Mimeo 1.01 that I built using a number of rare vintage components that I managed to obtain over the last few years. Note the gold plated 5 volt regulator, yellow 100 ohm pot and original style TI sockets and the Cinch edge connector.

    http://www.willegal.net/appleii/apple1.htm

    http://www.willegal.net/appleii/apple1-kit.htm

    Some of these components are very, very hard to find, and often expensive, when you do find them, so don’t expect to find these components in Unicorn’s standard parts kit.

    New Datanetics PCBs Due in 2-3 Weeks!

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    Despite very limited demand for these keyboard reproductions, I decided to pull the trigger on another batch. I think I am having more than enough made for everyone that has expressed interest, but in any case, let me know, if you are seriously interested in getting one or more.

    This time, I will be only selling blank PCBs, no brackets or anything else, so these are for the advanced hobbyist, only. I may do a brief instruction sheet, if I have time, but most of the info needed to build one up, is already on this blog (check the Datanetics category) or my website. I have to think some more about price, but I expect they will be around $80, including shipping. Even to me, this seems high for a blank PCB. However, keep in mind that these are fairly big boards by modern standards, and I only make a few in a batch.

    Like all my PCBs, they are made to a very high quality standard, right here in the USA.

    Latest Batch of Mimeos (version 1.01) Arrived

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    I made a few changes for this batch based on several years worth of feedback. First of all, previous purchasers should not feel left behind, as the changes are minimal, and would not be noticeable to the vast majority of vintage computer hobbyists. A person not aware of the specific change made would have to study the boards for a long time to find any difference. To give you the idea of the scope of the change, I’m calling this new version, “version 1.01”. I believe Mimeos have always been the best reproduction Apple 1 motherboards made, and this tweak raises the bar, just a little bit more.

    What follows is summary of changes.

    1) I changed the solder mask to matte. I’ve had a few people bugging me for years to do matte, and have finally been convinced to change. I did a matte run a few years ago on the Apple II rev 0, but thought the glossy look gave a superior “look”, though not quite as authentic. I have been doing glossy since then. Even a board made with matte solder mask will not exactly match with an original board, as PCB manufacturing technology has changed and is not possible to replicate exactly with modern processes. I suppose someone could attempt to replicate old manufacturing process, but keep in mind that many of the raw materials going into a PCB have changed since the 70’s, not just the solder mask. In any case, once you populate the board with components, the difference isn’t very noticeable. If I had to pick which bare board I was going to frame, I’d pick a glossy board, since it just looks a bit flashier. Be aware that he matte boards also look awesome, and will be a step closer to the original in appearance.

    2) A few minor changes were made to the silk screen, to better replicate an original board. Some of these minor differences from the original were found by me and some reported by other people. Most of the differences I’ve known about, are so minor, that no one other than me, ever noticed them.

    3) A few minor changes were made to the copper layer on the front. Same comments as with the silk screen layer.

    4) The board grid coordinate numbering and lettering along the edges has been slightly reduced in weight, to better match to original.

    5) Mounting holes were shifted ever so slightly to better match up with original Apple 1 mounting holes.

    So here is a partial view the rev 1.01 PCB. Unless something unexpected happens, I expect that this will the last update for a long time.

    Mimeo Version 1.01

    Mimeo Version 1.01

    Since I made changes, I need to assemble and test the new PCB before shipping PCBs. The good news is that the first board is up and running memory tests at this moment and testing should be complete by Tuesday. I should be able to accept orders starting on Wednesday and plan on shipping the first batch next Monday (10/14).

    Just a note to those looking for assembled systems, this prototype Mimeo needs an enclosure and soon I’ll be working on the building a prototype enclosure for this unit. I’ve also been working on a custom datanetics style keyboard for fully assembled systems that will use modern components.

    Apple 1 and Datanetics Backspace Working

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    While working on a micro-controller replacement for the MM5740/AAE keyboard decoder used on the Datanetics keyboard, I discovered a way to send the unique Apple 1 backspace keycode (0x5F). You need to connect line X4 of the matrix to one lead of a blank keyswitch and Y3 to the other lead of the same keyswitch. Then by holding down shift and pressing that blank key, you can generate the 0x5F needed to backspace the Apple 1 monitor.

    Note that you could also rewire the left arrow key of a MM5740 based Apple II keyboard to accomplish the same thing. Unfortunately there is no easy way to avoid the requirement of pressing the shift key to generate the correct code.

    New Version of PS/2 Keyboard Adapter Firmware

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    I had to program a new batch of micro-controllers, so I decided to make a few minor tweaks to the firmware.

  • The data invert functionality has been dropped . If you need inverted data, you can use external inverters to accomplish the same functionality. I don’t know of anyone that actually used this feature.
  • The jumper that used to control inverted data, is now used to control automatic reset and clear. Automatic reset system and clear screen upon power up is now disabled, unless the jumper is inserted. Several Apple 1 owners wanted more authentic operation, so now I disable automatic reset and clear screen feature by default.
  • A behavior that sometimes caused multiple resets when control-alt-delete reset sequence was used has been eliminated. Once reset occurs, all three keys must be released, before control-alt-delete can cause a second reset. The control-r, control-s, control-t reset functionality is unchanged.

    • Check out the manual that is downloadable from the PS/2 keyboard adapter page.