New Toy

September 1st, 2014


This is the first piece of gear to be used to expand my vintage computer hobby into a new direction.

Bicycle Wheel Rebuild

August 26th, 2014

It started as an assortment of parts

wheel parts for rebuild

wheel parts for rebuild

  • old Wienmann A129 rim (great touring rim)
  • new DT 14 gauge stainless spokes in two lengths
  • new DT spoke nipples
  • old greythumb nipple lube
  • new old stock malliard heliomatic hub
  • rim tape
  • old skewer
  • park nipple wrench
  • Jobst Bradt’s book: “The Bicycle Wheel”
  • and a few hours later I have a new wheel…

    wheel together and mounted onbike

    wheel together and mounted onbike

    One thing about truing your own wheels, they are going to be as true as the rim allows, if you have the patience to really fine tune them. I don’t have a runout gauge, but I wouldn’t be surprised if the runout measured 1/100″ or so on this newly built wheel.

    Total cost was about $100, but I ended up with a spare used hub in addition to the new old stock hub when I pulled the trigger on an ebay auction a couple of days before the NOS hub came up.

    Now to find a NOS hub for the front of my lightweight training wheel set – the bearings bind on that one unless the hub is put in the fork in a certain orientation.

    Dover Mini-Maker Faire Experience

    August 25th, 2014

    Dover, NH Mini Maker Faire

    Dover, NH Mini Maker Faire

    Just sharing some experience from the Dover Mini Maker Faire which was Saturday. I had Micro – Chess going on the Mimeo and Dave Ahl’s HI-LO in tiny SCELBAL (integer BASIC) on the SCELBI. It was busy almost the whole day, just a few fairly brief periods between visitors. It seemed a bit busier than Saturday at VCF.

    HI-LO was the perfect text game for casual visitors of all ages – simple to teach and quick and easy to play – I was impressed by the number of small kids that immediately proceeded to use a binary search algorythm to find the number.

    A lot of people tried a few moves on chess, but the user interface is so awful on the Apple 1 port of micro-chess – I had to train almost everyone – even though I had instructions posted.

    I met an original Mark-8 owner(still has his system). That guy added a digital group video card to his Mark-8 and made some improvements to it, which were used by later generation Digital Group video cards. Another person who was into SWTPCs in the day. Another person that was once vice president of the Boston Computer Society. And finally, another guy who worked with Draper Labs on the Apollo guidance system computer.

    There was a wide variety of exhibits from art and crafts to a young man who was building a neutron generator. If you have a mini-maker faire in your area, I’d say it would be worthwhile to show off your gear – you might meet some interesting people.

    List of all SCELBI PCBs

    August 20th, 2014

    I plan to reproduce all the SCELBI PCBs. There are 16 types of boards in all. The 1106-1108 8B boards are practically ready to be made. I’ll probably tell the PCB factory to start on them this week. This will mean that in a few weeks I’ll have 10 of the the 16 boards done. The really good news is that most of the remaining cards are only single width, so reproducing them should go much faster than the double width system cards.

    Here is the complete list of the PCBs that SCELBI Computer Consulting made and my reproduction status. The peripheral cards are listed in my most likely order of reproducing them

    Main System Cards
    1100 CPU – 8H/8B
    1101 Data bus buffer – 8H/8B
    1102 Input – 8H/8B
    1103 Backplane – 8H
    1104 Front Panel – 8H/8B
    1105 1K SRAM – 8H

    In progress
    1106 Memory Expansion – 8B
    1107 4K SRAM – 8B
    1108 Backplane – 8B
    1109 PROM – 8B

    Peripheral Cards
    2104 Teletype interface*

    Not started
    2105 Keyboard
    2100 Oscilloscope digital**
    2101 Oscilloscope analog
    2102 Audio Tape output
    2103 Audio Tape read

    * not as high as normal vector boards
    ** double width vector board

    Briefcase Apple 1 Sighting

    August 13th, 2014

    There are a couple of original Apple 1′s that were put in briefcases.

    One is owned by the “Main Personal Comptuer Museum” and is depicted on my registry page.

    The one of interest for purposes of this blog entry is shown in an image shown on a webpage put up by the Silicium Museum organization. I don’t believe that the briefcase unit is the actual Apple 1 owned by the silicium organization. In fact, since I don’t have good documented images of their unit, I am just a bit skeptical about whether Silicium actually has an Apple 1. My standards for posting original Apple 1 information has risen since I added the Silicium unit, and if I recieved a similar report today, I might not have added their unit to the registry, at least until I recieved a good image.

    However, it is interesting that I just got another historic look at this same briefcase Apple 1. It was shown on the program Computer Chronicles, which has it’s shows archived at the site It can be seen at the beginning of a show entitled“Apple II Forever”.

    I may have to add this unit to the registry, as a missing historic unit. There is a reference in the show to it being a museum piece. Since the show might have been taped in California, maybe it’s still sitting in some museum vault in the Bay Area.

    By the way, there is no better way to understand the history of personal computers than to read vintage publications and view vintage videos. The archive of “Computer Chronicles” show is priceless. Check out Bill Gates participating in the Computer Bowl II.

    why is everything breaking?

    August 11th, 2014

    Within the last few weeks I’ve had the following problem with mechanical devices.

  • rear hub on bicycle
  • crankcase gasket on lawn mower
  • 3TB hard drive used for backup for three household computers died
  • coolant leak in 2009 Dodge Caravan
  • and a CD/DVD drive on a PPC Mac mini used for backup and connection to old peripherals is showing signs of imminent failure
  • My son says that I am having problems because all my stuff is old.

    Except for the the coolant leak, I’m getting replacement parts and doing my own repairs/replacments. I’d probably look the coolant leak, except that I just finished replacing the crankcase gasket on the lawn mower engine, and don’t feel like diving into another engine right now.

    I’ve had a lot of issues over the years with the lawn mower which was built in 1994 and would replace it with a new one, except that repairing it is so much less expensive than replacing it. For instance, the crankcase gasket, PTO oil seal, and a welded muffler (which I found was busted when I pulled the engine to repair the crankcase gasket) cost me all of $35 to repair or replace. That wouldn’t even pay the taxes on a new mower.

    When I pulled the crankcase cover off, I was expecting to see an engine on it’s last legs, but the internals looked good. Over the last couple of years, it was using a lot of oil, and I was thinking that the rings were going, but now I think that the oil was just leaking out of the crankcase. Now I think that the engine might last a few more years.

    SCELBI 8B update

    August 11th, 2014

    Hi SCELBI fans,

    Based on scarcity of reports, it may not seem like it, but I am still actively working on the SCELBI 8B card set. It is pretty tedious work, and reporting every new set of tweaks to the layout is not very exciting, so I haven’t been reporting ongoing progress.

    To be honest, I prefer exploring new projects, rather than revisiting old ones. Though the SCELBI 8B is “new”, it leverages so much of the 8H design, that it really seems more like revisiting the 8H, than doing something new.

    At this moment, I am going through final design checks of the SCELBI 8B backplane, memory expansion, and 4K SRAM PCB layouts. I already have quotes and have done DFM checks with my PCB supplier. I think I will probably build up an very basic 8B system without I/O in a temporary chassis in order to get these cards checked out. This is so I can offer the PCBs for sale for those of you who can’t wait for the whole package. Based on what I know at the moment, I might be ordering PCBs in as little as a week or two from now.

    The chassis sheet metal and the EPROM card will come a little later as follow on efforts.

    After that, my next efforts will probably be the SCELBI keyboard and oscilloscope interfaces. Those will be “new” to me, so will be a lot more fun to do than the 8B has been. The O-scope interface poses some interesting challenges, as we don’t have any original software for it. We will have to craft some drivers using only the hardware implementation as a reference.

    The World War 1 Meuse Argonne Campaign compared to the World War II Battle for Normandy

    August 2nd, 2014

    This is a follow up to a previous post about my grandfathers involvement in World War 1.

    World War 1 seems almost forgotten these days. Compare the little remembered Meuse-Argonne Offensive with the Battle for Normandy. Each of these campaigns is considered a major contributor towards ending a tragic war.

  • The Meuse-Argonne Offensive lasted 47 days from September 26,1918 till the end of the war, November 11, 1918.
  • The Battle for Normandy lasted 86 days, from June 6,1944 to August 30, 1944.
  • The Meuse-Argonne Offensive involved 1.2 million American and French troops and about 450,000 German troops.
  • The Battle for Normandy involved 1.45 million Allied troops and about a million German troops
  • During the the Meuse-Argonne offensive, the French and Americans suffered about 187,000 casualties and the Germans about 100,000 casualties.
  • During the battle for Normandy, the Allies suffered about 225,000 casualties and the Germans around 425,000 casualties.
  • It seems a bit of a shame that the loss, pain and suffering of hundreds of thousands of people in World War 1, has nearly been forgotten.

    Eventful bike ride

    July 20th, 2014

    I had some issues during yesterdays bike ride.

  • strange sounds started eminating from the rear end. I stopped to check it out. Since it sounded a bit like the twanging of spokes and just last week I experienced a broken spoke, I decided to tighten the spokes on one side half a turn.
  • after the noise continued, I made a decision to continue the full ride, at a slow pace, instead of cutting it short.
  • a few miles later the noise increased and I got off the bike to check it out. turns out the bearings in the rear hub where completely shot
  • I did have a phone with me, but since it was 7:00 AM and the rest of the household are late risers, I decided to walk home
  • The bearings were so bad that the wheel would not track within the frame even when walking. Intermittant tire rub on chain stays, for the full walk home
  • about 1/3 the way home I slightly twisted my ankle. Started regretting deciding to walk home in cycling shoes
  • another mile and I twisted my ankle again – much worse this time
  • a little ways further on, I decided to remove the cleats from from my cycling shoes to make walking easier
  • cycling shoes slipping going up a steep hill
  • got home around 10, making it a 15 mile “ride” at an average speed of under 4 miles an hour
  • took the rear hub apart and found only a single broken ball in the right side races. The rest of the balls on that side must have disintegrated and fell out
  • the race in the right side cone is bad and an internet search reveals that cones are no longer available. Guess I’ll find a replacement hub. Meanhwile I’ll use my spare set of wheels
  • More Vintage Fonts – The SCELBI Front Panel Logo

    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.