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Re: [midatlanticretro] Altair 680 Project Update

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  • B. Degnan
    Dan, I re-read your pages and the manuals I have. Frankly it s confusing. Here is how I interpret what I have read:
    Message 1 of 48 , Mar 3, 2007
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      Dan,
      I re-read your pages and the manuals I have. Frankly it's confusing.

      Here is how I interpret what I have read:

      http://ragooman.home.comcast.net/files/vintage/altair/assypg16sm.pdf
      ...seems to indicate that only If I am using a baudout TT I need the 74LS74
      chip in the L slot, otherwise no IC is needed in IC L.

      ...but then...

      Take a look at page 17 of 37:
      http://www.vintagecomputer.net/MITS/680/MITS_Altair_680b_Theory_of_Operation_Manual.pdf

      How do you interpret this? This is my source for why I think that the
      74L123 is needed in slot L.

      Questions:
      1) Do I need *any* chip in the L slot?
      2) Do you have a working system that uses a terminal? If you have a
      working system than I would like to try to match your configuration, being
      that it works! Schematics confuse me.
      How does your motherboard I/O circuitry compare with mine?
      http://vintagecomputer.net/MITS/680/pictures.html

      Thanks very much.

      Bill

      At 06:36 PM 3/2/2007 -0500, you wrote:

      >Well, it seems very odd that with the same rev1-6X motherboard that MITS
      >would use two different IC's. I checked your pics of the motherboard and
      >its the same as mine. I also have the round toggle switches on mine.
      >Have you check the Assembly doc PDF's I posted online to compare ?
      >
      >All I remember is that the 680 had a front panel with a different color,
      >aside from a different rev motherboard too I suppose. I recall seeing a
      >pic online somewhere but I don't seem to have that bookmark.
      >
      >I posted sheet 2(rt.half) from my schematics showing IC L being a
      >74LS74, the pinouts checkout accordingly.
      >http://ragooman.home.comcast.net/computers_altair680.html
      >
      >=Dan
      >
      >[ My Corner of Cyberspace http://ragooman.home.comcast.net/ ]
    • Evan Koblentz
      DG Eclipse S/140 from a couple of months ago, now on display in our museum, next to Perkin-Elmer 3120.
      Message 48 of 48 , Mar 20, 2011
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        DG Eclipse S/140 from a couple of months ago, now on display in our museum, next to Perkin-Elmer 3120.
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