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1220Re: [midatlanticretro] Which version is it, Altair 680 or 680b ?

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  • billdeg@aol.com
    Sep 4, 2005
      From July 1976 on I believe they were the "b's" If your board had 1975
      printed on it then I would be more confident that is was a "non-b"

      Another thing to check would be the monitor ROM, they were different in the
      two models. You might be able to get the model by looking up that chip. If
      you have BASIC for the 680, it may make mention in the documentation of the ROM
      monitor required, and from there you can infer the model.

      The main motherboard of the 680b will have a space at position L for a
      "Baudot serial" chip, look for a chip with 74LS74 on it. If you have this, it's a

      I have an SWTPc 6800 which is similar to the 680, but not exactly. The 680
      used S-100 bus and the Altair has a A-50 (Altair custom 50) bus. You can load
      programs from the SWTPc onto the 680 with minor modifications (I have been


      In a message dated 9/3/2005 9:14:42 PM Eastern Standard Time,
      ragooman@... writes:

      > One thing I noticed after I took this part, the mainboard actually says
      > this
      > MITS 1976
      > 680 MAINBOARD REV 1-6x
      > I hope somebody might be able to help identify this model. I'm thinking
      > this is actually a 680 and not a 680b, am I right ?
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