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Re: [midatlanticretro] Altair 680 Project Update

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  • Bob Grieb
    Bill, I have the TI TTL data book from that era which lists both L123 and LS123 one-shots. The timing formulas are a little different, but the parts are very
    Message 1 of 48 , Mar 1 4:55 PM
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      Bill,

      I have the TI TTL data book from that era which lists
      both L123 and LS123 one-shots. The timing formulas are a
      little different, but the parts are very similar. I am thinking
      that you could probably use an LS123, and change the resistor
      between Rext/Cext and VCC a little to get the same pulse width.
      I can e-mail you the data sheet if you want. It might be very hard
      to find a 74L part these days. (Or not. I haven't tried)

      Bob Grieb


      --- billdeg@... wrote:

      > Unfortunately no, it has to be the 74L123.
      > bd
      >
      > > billdeg wrote:
      > >> I am learning a lot about the Altair 680. It appears that the
      > memory
      > >> is OK, but as you can see from the latest pictures...
      > >> http://www.vintagecomputer.net/MITS/680/pictures.html
      > >> ...I am missing a chip, a 74L123. Might anyone here have a spare
      > lying
      > >> around?
      > >>
      > >>
      > > Bill,
      > >
      > > Would a 74LS123 be a suitable replacement?
      > > http://www.unicornelectronics.com/IC/74LS.html has them for 27
      > cents.
      > >
      > > Cheers,
      > >
      > > Bryan
      > >
      > >
      > >
      > >
      > >
      > > Yahoo! Groups Links
      > >
      > >
      > >
      > >
      >
      >
      >




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    • 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 1:01 PM
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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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