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1138680b Project Update

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  • billdeg
    Mar 1, 2007
      Here are my latest 680b restoration project notes.

      1) Steve Shepard sent me an ACIA monitor prom which seems to be
      working. I toggled through the first 26 or so address bits and the
      data matched the prom code. No monitor dot prompt however. Checked
      using two terminals and hyperterminal/laptop.

      2) Also with help from Steve Shepard, learned that the IC in position
      L, 74L123 is missing. I located the position in the schematic to
      match/confirm. Steve suggested that I review every chip and
      connection to be sure nothing else is missing/incorrect. I am in the
      process of doing this now. I assumed that the missing IC was supposed
      to be that way, my mistake!

      3) I have taken hi-res photos to aid in the analysis. I have posted
      the new pics at the *bottom* of this page, if anyone is interested. I
      also have a link to some of the manuals.

      4) I checked my chips on hand, I do not have a spare 74L123. If
      anyone here has one for sale, please let me know. I found a site that
      may be able to help, but I have not called them.

      Summary - Given (A big assumption) that all of the soldering is OK, I
      hope that installing a 74L123 in IC L will get me to a dot prompt
      finally. You can see from the pictures that this is definitely a kit,
      and that some connections were changed at some point.

      That's all..off to work!
      Bill D
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