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    IOB6120 questions

    Thank you so much for sharing this. There's a lot there, and it will be fun to look through it all. Dave
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    IOB6120 questions

    I found some TE28F400CEB120 parts on ebay, which can handle a 5V supply. They ship from California and have the textured appearance, so I suspect they are genuine.
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    IOB6120 questions

    Thanks Vince! Also, I see that I can get the intel TE28F400 parts on ebay. Would that be better than a 29F400 from Mouser (Alliance Memory)?
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    IOB6120 questions

    Hi all, Somewhere around 2010 there was a group buy of IOB6120 PCBs and parts. I got all my parts from the gentleman who arranged the buy and built up the board without really critically reviewing the parts, and when I attached it to my (working) sbc6120, the whole system was unresponsive. I...
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    DFW Retrocomputing Meetup, Winter 2024 edition

    Hello All, It's time to start planning for the next DFW Retrocomputing meetup. The first Retrocomputing Meetup of 2024 will be on January 21, brought to you by the DFW Retrocomputing Meetup group and the Vintage Computing Collective of North Texas. Our winter meetup is generously sponsored by...
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    Modern Vector Art on the Tektronix 4050 microcomputers

    Beautiful artwork. Those machines are amazing. Too bad they are so rare. I saw your displays at the VCF Southwest, but alas, I only had a couple of hours there and I didn't have a chance to dwell there. Where are you in Texas? It would be awesome if you made it to one of our quarterly...
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    Osborne 1 New mechanical keyboard

    Very nice project. I like the pure hardware approach.
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    Theory of operation of H7441 regulator

    Just to clarify: By "Larger error signals" I meant larger overvoltage error. Undervoltage will generate larger feedback voltage and stretch the pulses.
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    Theory of operation of H7441 regulator

    Shoot, somebody posted a description already! I had this in draft since last night, and just did some edits and posted. At a glance the breakdown seems to be similar.
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    Theory of operation of H7441 regulator

    I will have to go through in detail, but at a glance, this is what I am seeing: - D1/F1/C1 provide fused rectified unregulated DC (voltage depends on what is hooked to J1). - Q4 provides an unregulated 12V to power the rest of the regulator -E1, as you said, is an oscillator providing a pulse...
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    Osborne 1 New mechanical keyboard

    That's the difference between the "5-pin" keys and the "3-pin" keys. Cherry MX and non-Cherry brands will have both options. The 5 "pins" refer to the two contact pins, the center post, and the two alignment posts. The "3 pin" variety does not have the alignment posts. The 3-pin variety is...
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    How to 'trace' vintage artwork in a modern CAD program

    I was referring to displaying the logo as a background to be traced. Kicad 7 has a button (icon of mountains and sun) along the right-hand side toolbar to import a bitmap for viewing/tracing. In general, it's better to work with vector images like DXF or SVG rather than bitmaps, because they...
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    How to 'trace' vintage artwork in a modern CAD program

    Got it. You have a couple of options: 1) Find or create a DXF of the logo in a drawing program like Illustrator or Inkscape, then import the DXF to the desired layer You can convert closed shapes to polygon or pour zones. If you use pour zones, then you can place smaller "keepout" zones...
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    How to 'trace' vintage artwork in a modern CAD program

    There is a way to get curved traces. It's a little indirect, but the results are nice. You need to install the mitxela curved tracks plugin, by selecting it in the plugin manager and installing. First, in the PCB routing settings, select any-angle traces. Then using a photo as a template...
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    Anything worth seeing in while in Dallas TX?

    Sadly, no computer museum or the like. Perhaps a decade ago, you might have stopped by Tanners, Electronic Discount Sales, or Computer Reset. Now all are closed, sadly. Here's a great writeup on Hackaday, for nostalgia. However, you might still have enough time to stop by the National...
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    What backplane is this?

    Thanks to all of you! I suspected it to be an 8/a backplane, but despite searching, I couldn't find a match. But this is clearly the same. I have a set of 8/f cards, meaning the front panel uses LEDs. I have the full CPU set (without EAE, but with extended addressing), a 4K core, and Vince's...
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    What backplane is this?

    Hello, A while back I picked up a DEC backplane on ebay. The description was not detailed, and the photos were not great, but it looked like a DEC PDP-8 or PDP-11 backplane, and I have cards for both, just waiting for a backplane. I do not recognize this backplane, and searching for the...
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    Recreating the Ferguson Big Board

    This looks fantastic!
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    Osborne 1 New mechanical keyboard

    You might want to check out the unified retro keyboard project. It is meant to provide exactly what you are looking for: a parallel ASCII keyboard with a classic period-correct feel, that can be customized to taste, and also can fit a number of vintage computers. The osborne is not added yet...
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    Do keycaps from 605-4115-0 RFI-style keyboard fit cherry MX keys?

    I've asked this question on applefritter, and got one response that the keycaps might not fit Cherry MX keys, but this did not seem definitive. Does anyone either know the answer, or does anyone happen to have one of these keyboards (or keycaps), that might be willing to test the keycap fit on...
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