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Thread: Honeywell 200 resurrection

  1. Default

    I look forward to your progress.

    Are the ICs PMOS? Do they have negative supply voltage? In the early 70s TI made PMOS ICs for their first calculators. Maybe that's the P in your part numbers?
    Last edited by ClausB; November 24th, 2012 at 05:57 AM.

  2. #32
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    Nov 2012
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    RobS,

    Sounds like great progress. It's truly amazing what can be done with enough determination & resources!

    I, too, look forward to progress. Maybe a few photos too.

    Clay

  3. #33
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    Sep 2012
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    Kent, England
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    The ICs use +5 volts and have feedback capacitors back to an intermediate connection point within each gate. We assume that they are DTL. The current levels on inputs point to that. I have schematics dated 1969 which use them and some ICs with 1969 batch numbers on them but that's the only clue to when they were introduced and they probably date from earlier.

  4. #34
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    Sep 2012
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    Kent, England
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    Well, this is what's meant by starting from scratch, the main frame of the mainframe so to speak. I was about to give it to a scrap metal dealer when I relented and put all the parts back to start this project.
    Frame 2.jpg
    ... and here's my stockpile of original Honeywell components. Also Marcel has contributed the memory components but they aren't shown here.
    Components 2.jpg
    We are taking photos but they'll have to wait until I get that website up.

  5. #35
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    Sep 2012
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    Now we're really starting from scratch. One backplane is too restrictive on the design, so I've removed all the components again and arranged to take the frame to a foundry to get a copy made. That will enable us to put the CPU and memory on separate backplanes as in the original H200 design. The H200 hardly qualified as big iron, but it's certainly small aluminium. I would have loved to follow David Gingery's example and done the work myself, there even being a few crucibles in my garage just in case, but there's just too much for me to do already.

    We don't have enough sockets to fill two backplanes, but I am considering several measures which will enable the logic boards to be spread across the two. One measure may be to get additional socket cases made by a 3D printing service. Pins can be transplanted from other unsuitable edge connectors to complete the sockets. I already have a stockpile of over 700 wirewrap pins which will do. Also Marcel believes that sockets from Univac machines may be directly suitable, if there are any going spare anywhere.

    It would be poetic to use sandcasting, one of the oldest known ways of making shapes, in conjunction with 3D printing, one of the newest, on this project.

  6. #36
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    Dec 2005
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    Toronto ON Canada
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    How about a closeup pic of those 'sockets'?

  7. #37
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    Sep 2012
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    Kent, England
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    Here's the top view. The connectors are in blocks of five. It might look like ten but each board uses two across. The pins are spaced at 0.125 inch pitch. The break-apart provision in the centre suggests that they evolved from earlier eighteen pin connectors. I think earlier boards were narrower than the H200 ones. Marcel said that the eighteen pin connectors are compatible with Univac but the gap between the pairs is a different width. For the H200 it's exactly four pins, half an inch. If the gap is the only problem then one could put Univac connectors side by side with a half inch gap and let each H200 board straddle two.
    Socket block2.jpg
    Rob - http://www.honeypi.org.uk
    The Internet is a winch to get your project off the ground ... but always have a parachute handy.

  8. #38
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    Sep 2012
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    Kent, England
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    Here's a bit, several bits actually, of a Honeywell 200 memory.Bits of memory.jpg The picture is rotated 45 degrees to frame up the central core, so the red and green diagonal wires are the x and y axes, the vertical green wire is the inhibit line and the thin red wire parallel to the green diagonal wire is the sense line. That's how I understand it anyway. The quality of the picture isn't too bad considering that the microscope I used is even older than the Honeywell 200, having been bought at a police station sale of lost property by my late father-in-law in the distant past, so I believe. I have some other Honeywell memory planes which have five wires through each core, but they work differently from these and weren't used in the H200.
    Rob - http://www.honeypi.org.uk
    The Internet is a winch to get your project off the ground ... but always have a parachute handy.

  9. Default

    Cool micrograph! - from a fellow glider pilot (Schweizer 2-33, 1-26, Grob 103, Blanik L-13).

  10. #40
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    Sep 2012
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    Kent, England
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    Appearances can be deceptive. I am no more a glider pilot than Honey Pi will be a real Honeywell 200; both are a matter of creating a convincing illusion. My avatar photo was taken while on a day out with our pensioners' group several years ago. I did get a flight with an instructor though and even took the controls for a while. However, my only other experience of flying was as an RAF cadet in my school days and flying a glider is different from flying aerobatics in a Chipmunk with an engine. The winch launch was definitely memorable though, getting things happening very quickly indeed, just like finding like-minded people on the Internet is.

    The backplane is now at the foundry waiting to be copied but it won't be done until after Christmas probably.
    Rob - http://www.honeypi.org.uk
    The Internet is a winch to get your project off the ground ... but always have a parachute handy.

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