Archive for the ‘Vintage Computing’ Category

More Vintage Fonts – The SCELBI Front Panel Logo

Thursday, July 17th, 2014

For a while I’ve had an interest in vintage typefaces. This interest stems from my efforts to reproduce vintage literature and the logos.

When I made my SCELBI front panels, one of the challenges I had, was to match the font for the SCELBI logo. Here is an image of the overall front panel.

SCELBI front panels

SCELBI front panel

and a close up of the logo.

Scelbi logo- close up

Scelbi logo- close up

Even though this is a variant of the omnipresent Helvetica, finding a digital font to match was harder than you think. After searching through dozens of variations of Helvetica and derivative fonts, in the end, I choose to use the very similar Helvetica Black. In some cases in the past, I have used Adobe Illustrator to manually recreate logos and such, but recreating characters accurately is extremely difficult and it is vastly easier to use off the shelf fonts.

Scelbi Logo in Helvetica black font

Scelbi Logo in Helvetica black font

It’s a pretty close match, but in reality the original logo’s characters are just a bit wider, so it’s not perfect.

I’ve known for a while that the single largest source of typefaces for printers and advertising people back in those days was Letraset brand rub on transfers. Back in the day, anyone that had anything to do with the printed word, would have had a Letraset reference manual, which contains hundreds of fonts and other visual goodies. Vintage Letraset manuals are available from used book sellers and even on ebay. Recently I picked up a 1981 edition.

Letraset Reference

Letraset Reference

One the first things I did when I got this guide was to determine if I could find an exact match for the SCELBI front panel logo. Here is what I found on the page with bold type Helvetica fonts.

Letraset Helvetica Bold

Letraset Helvetica Bold

If you ask me, plain old Letraset Helvetica Bold is an exact match and was the source for the lettering on the original panels. Now I’m just going to have to figure out the best way to digitize and scale the example letters found in the Letraset guide for my next batch of front panels.

Keyboard Gizmos

Tuesday, July 15th, 2014
parallel keyboard gizmos

parallel keyboard gizmos

Here is a popouri of parallel keyboard projects that I have been involved with designing.

Not shown

  • A simple single chip AVR PS/2 to parallel keyboard adapter that I forgot about when I assembled the items for this picture.
  • At top is:

  • A reproduction Datanetics keyboard
  • At bottom, from left to right…

  • Home etched/prototype PS/2 to parallel keyboard adapter
  • Production PS/2 parallel keyboard adapter configured for Apple 1/Mimeo
  • Production PS/2 parallel keyboard adapter configured for Apple ][. The latest version firmware can also be used with other vintage computers
  • Home made Apple ][ keyboard to Apple 1/Mimeo motherboard dongle with clear switch - based on schematic at Wendel Sander's Apple 1 site
  • Production Vintage Micros Apple ][ keyboard to Apple 1/Mimeo motherboard dongle with clear switch. Similar to home made one
  • Corey Cohen’s parallel keyboard multiplexor. Automatically accepts and switches input from two different parallel keyboards to a single destination motherboard.
  • Not shown are a number of projects that I have started, but not completed (yet)

  • Datanetics replacement using modern components
  • MM5740 replacement using modern micro controller
  • And then there are the projects that never got past investigation stage.

  • ADB bus to parallel adapter
  • PS/2 Apple IIe keyboard adapter
  • It’s really hard to imagine that I have spent so much time mucking with simple parallel ASCII keyboard technology.

    Vintage Micros has Apple 1 motherboard to Apple 2 keyboard dongles available.

    Sunday, July 13th, 2014

    I helped with the PCB layout for this cute little dongle. It has a clear screen switch, which isn’t normally available on an Apple II keyboard and does the rewiring necessary to connect a stock Apple II keyboard to an Apple 1, Mimeo or other clone. These are not needed for replica 1s, which has the keyboard pinout necessary to work with Apple II keyboards.

    Here is one in action, hooked up between the keyboard and the Mimeo.

    Keyboard Dongle

    Keyboard Dongle

    They are being sold by seller vintagemicros on eBay: ebay listing

    One word of caution – be sure to connect pin 1 of cables to pin 1 on PCBs. If you reverse them, you will probably blow the 7404 on the keyboard’s encoder board.

    One last thing, I connected pin 4 of the keyboard socket to the clear screen input on the Apple 1. Pin 4 is normally not connected on an Apple II keyboard, but if you make the keyboard encoder mod to use the repeat switch as clear screen input as described on Wendell Sander’s site, it will work without any further wiring changes.

    SCELBI 8B update

    Friday, July 4th, 2014

    Here is a composite image showing the great progress that has been made on the 4 boards that need to be done for the SCELBI 8B.

    Composite Image of 8B Boards

    Composite Image of 8B Boards

    Still a ton of tweaking and fine tuning needs to happen, but you can almost see the light at the end of the tunnel. I also need to find some time to figure out what I’m going to do for the custom chassis.

    The backplane layout is for all intents and purposes done. The memory expansion card is next closest to complete. I haven’t done much with the PROM card, but I’ll do a complete review of it. The curved traces promise to require a lot of effort to match up to the original. The 4KSRAM cards need a lot of work and since the original has curved traces, it will take an extra effort to finish.

    I’ll be at the MakerFaire in Dover, NH Aug, 23rd

    Tuesday, July 1st, 2014

    I’ll have a Mimeo (Apple 1 clone) and a SCELBI 8H clone up and running and if you come, you’ll be able to see and operate them.

    MakerFaire Dover Flyer

    I hope to see you there.

    Brain Board Manual Errata

    Tuesday, July 1st, 2014

    I have a mistake in my Brain Board Manual versions 5.3 (current version) and lower. On page BB:12, the last switch settings are incorrect.

    Dual Bank Mode – Either high bank of Brain Board or low bank of Brain Board is selected

    should be:



    Switch 3 and 4 settings are backwards in the manual. When I get a chance I’ll update the PDF that is on my Brain Board web page. I already printed manuals for the remaining inventory of Brain Boards, so will hand edit those manuals.

    SCELBI 8B Backplane Progress Being Made

    Tuesday, June 10th, 2014

    Lately. I’ve been making some good progress on the 8B backplane. Hopefully in a few more weeks and I’ll have it in good enough shape in order to declare it finished. I’ll probably just go ahead and get it made when it’s ready, even though I have a lot of work to do on the other 8B specific cards.

    There is quite a bit involved in building an 8B chassis and 8B builders can start on the chassis while I finish the rest of the cards. Anyway the CPU can be checked out by jamming in instructions, without memory being present. The front panel, CPU, DBB, and input boards are completely identical to the 8H design and I still have some of those PCBs in stock.

    One thing I’m going to have to think about a bit, is whether to make a batch of SCELBI custom sized chassis or not. A BUD AC413 can be made to work, as it is nearly the correct size, just a 1/2″ short, other dimensions being right on.

    Status of the other 8B specific cards are:

  • memory expansion – I haven’t started on this one, but it is the most basic of the 8B specific cards, so should take the least amount of time to do
  • 4K SRAM- designed to accept 2102 static ram – this card is pretty far along, maybe half done.
  • EPROM – designed to accept 1702 EPROMs – I have a tested, working layout for this card done by someone else. The original layout artist did a good job, but there are a few things I want to change. I will completely go through it to make the layout details match the original as much as possible.
  • Why Does Someone Recreate the Apple 1 in Exacting Detail with Original Parts?

    Friday, May 23rd, 2014

    This is the essence of a question someone asked on Applefritter.

    Here are my thoughts on this topic.

    It’s really not that complicated, people do this stuff cause it’s fun for them. This hobby is not for everyone. It’s about personality, if you don’t get it, you either haven’t been exposed to enough of the possibilities, or you have a different personality.

    This question is really applicable to many different vintage systems with similar followings – the Apple 1 gets a lot of press because it’s the very first computer of a very successful company that, at the moment, happens to be near the top of it’s game.

    There are three main activities in this hobby, with a little different motivation for each.

    1) The collector – For some people, it is a lot of fun to own an item of significant historic value.
    2) The operator – For some people, it is a lot of fun learning how to build or restore and operate a vintage computer.
    3) The developer – Some people find it fun to expand the capabilities of vintage computers, providing capabilites to vintage machines that could not be dreamed of, back in the day.

    There is a lot of crossover between the people participating in each of these activities.

    For some of the rarer computers, you may decide it’s better to use a reproduction, rather than risk damage to an original machine or you may not be able to find or afford an original machine.

    The reasoning behind installing date code original parts and making the reproduction as accurate as possible, is two fold.

  • First- tracking down these parts is like a scavenger hunt and can be a lot fun in itself.
  • Second- making a reproduction more like an original, raises the level of pride and satisfaction in the end result to a significant degree.
  • In case you are trying to decide whether you might enjoy the hobby or not, consider this: how could you decide whether you might or might not like swimming, without going in the water?

    Vintage Humor

    Friday, April 18th, 2014

    I found this in Volume 1 – Issue IV of the SCELBI Computer Digest, which can be found online at



    Updated PS/2 Adapter Firmware (version 3.0)

    Thursday, April 17th, 2014

    I have enabled stretched as well as the possibility of an acked strobe output on my PS/2 adapter. I’m calling this version, 3.0. This should make it easier to use the adapter with some vintage gear, such as an OSI system, which doesn’t latch strobe, but only polls for it. Read the updated doc on my PS/2 adapter page.