Category Archives: Apple 1

About Apple 1 computers

VCF – great time for a vintage computer nut

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Last weekend was VCF east 7.0. I spent the weekend among other vintage computer nuts. It was a great time, and I highly recommend going out of your way to spend the weekend, next time this event is held. This event can not be fully appreciated unless you take the time to listen to the lectures, and see the museums that comprise the info-age facility.

Among the highlights was seeing part of an Apollo Guidance Computer, something I studied last year. I was thinking of doing some kind of recreation at one point.

Apollo Guidance Computer

Here is my exhibit, where I showed the Mimeo, A2 rev 0, brain board and PS/2 keyboard adapter. My exhibit won the gold medal in the preservation/recreation catagory.

my VCF east 7.0 exhibit

Here are the posters I displayed in my exhibit.

First the Apple 1/Mimeo poster

A1 poster

A1 poster

Second the Apple II/rev 0 poster

A2 poster

A2 poster

Note on BB assembly, Version 5.1 PROMs shipped, and Why Is the BB Upside Down?

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For people that still had the FCS, 4.0 PROMs, version 5.1 PROMs were shipped on Monday and should be in your mailboxes soon. I will only be updating version 5.0 PROMs upon request. The only difference between version 5.1 PROMs and 5.0 PROMs, is in the power up screen and it doesn’t affect operation in any way.

Though assembly is really straight forward, there is one thing to watch out for when assembling Brain Boards. Where the traces run between pads, the soldermask reveal extends right up to the edges of the traces and, on some boards, where registration isn’t perfect, the solder mask reveal may expose a tiny part of the trace. There is potential here for shorting the trace to the pad when soldering a component to this pad.

Brainboard-soldermask

When soldering these pads, be careful that you don’t accidentally bridge the gap between the pads and the adjacent trace. If you can’t get rid of the bridge with a solder wick or solder sucker, the easy fix is to cut the solder bridge with a hobby knife. Check continuity with an ohm meter to make sure the connection is broken.

Is the Brain Board Designed Upside Down?

It’s funny that no one has questioned or commented about the upside down layout on the brain board. This was done on purpose because of the vastly improved layout possible with upside down chips. The layout of the address and data bus connections between the 27c256 and 74LS244 sockets and the edge connector would be much more complicated if the chips were right side up. Flipping the 27c256 right side up moves the data bus connections of the 27c256 to the opposite side of the chip from the 74LS244 and Apple data bus. Also, all the lower address lines would have to be crossed to properly connect the 27C256 to the Apple bus.

Once I flipped the 27C256, I figured I had to flip all the chips and the silk screen to prevent confusion and mistakes during assembly.

Version 5.1 Brain Board Manual posted on BB page

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The only difference between version 5.0 and 5.1 is the power up screen. The original A1 had alternating “_” and “@” signs with the @ signs flashing. The @ signs actually disappeared during the flash off.

With version 5.0, I had the @ signs flashing between normal and inverse instead of completely disappearing. With version 5.1, this was fixed to have the @ signs disappear during flashing, like on the original Apple 1. I actually had it right on earlier versions, but made a change to dramatically improve initialization time in version 5.0 and created this discrepancy at that time.

I’ve been shipping 5.1 since 4/1/11, and have heard no reports of issues. In fact, other than the flashing @ signs, I haven’t heard of issues with any of the versions, other than someone verifying the memory corruption bug with 4.0, that I previously reported in my blog.

Because the difference is pretty small and does not affect operation in any way, I don’t intend on automatically shipping updated 5.1 PROMS to those who already have 5.0 PROMs. If you have version 5.0 you can request an update or if you have a PROM burner, I can send you an Intel hex file with the new image.

There are still a few people with version 4.0 that I owe an update to – I plan on shipping version 5.1 to you around the end of the month.

How many original Apple 1’s are left?

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Well 32 are clearly documented in my registry.

Another 4 are listed on the registry page, as most likely to exist, but since I don’t have good enough information to eliminate them as duplicates, I have them listed as probable.

I have less concrete information on 4 or 5 more. Some of these may be listed soon, as the owners are planning on providing more details to me in the near future.

That puts my count of probable units at around 40. Keep in mind that I’ve only been investigating this for about a year and a half.

How many more are in private hands? That is anyone’s guess, but I’m sure that a number of owners don’t want to publish the fact that they own a collectible computer that could be worth as much as $200,000.

It wouldn’t surprise me if the number of undiscovered units was as high as 20 or 30. That means the previous estimates of under 50 remaining Apple 1’s is probably low and the actual number could be as high as 60 or 70, perhaps even more.

On the other hand, maybe everyone who has an Apple 1 has had something published on the web about it and there are only 40 left. What do you think?

Brain Board Update #2 – Beta Almost Complete

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The Brain Board/Wozanium pack web page is up and includes a link to the Beta Manual with has all kinds of information about the implementation. I have a little more to add, including an example downloadable driver that allows a user to control the machine through a super serial card.

I have had some good feedback from the Beta team. Several improvements have been made to the Wozanium firmware and will undergo testing this week. I plan on starting general shipments on 3/21/2011.

Cost for kits will be $59 with free shipping in USA and $10 shipping internationally. I also plan on offering built up units, once I get through any flurry of initial kit orders. Send me an email, if you have any questions.

Brain Board Update

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I have shipped several Beta kits to some Mimeo builders who also have Apple IIs. Once I incorporate any feedback from the Beta Testers, I’ll open up for ordering. Hopefully this will take only a couple of weeks. My own testing of the production board has revealed no bugs.

In some ways, this is the most complex retro-project I have yet attempted. There was a pretty decent blue print for the Apple 1 and Apple II projects. The complexity involved making sure I didn’t overlook any of the content in the blue print and filling in a few blank pages. The Brain Board project involves creating a way to map the blue print from one fairly complex architecture into another. It also involves mapping the software systems along with the hardware systems. With the motherboard projects, the software was a given. A similar project was the PS/2 to ASCII keyboard adapter, but that mapping is much more constrained.

Several folks have suggested I take pre-orders for this project. Though demand on this project is hard to estimate, I think I have enough parts on hand to supply immediate demand and pre-orders are not necessary.

I have decided to classify this kit as a level 1 kit – it is very easy to build. If you can figure out which end of a chip has pin 1 and have a decent soldering iron, you should be able to build it. Here is a list of projects that I have offered with their skill levels.

1) Apple Cassette Interface (stocked), Brain Board (shipping soon)
2) PS/2 keyboard adapter (stocked)
3)
4) Apple 1 (stocked), Apple 2 rev 0 (discontinued)
5) Datanetics keyboard (several PCBs left)