Yeah, that looks like quite the effort; thanks, Henner!

But I'm looking for that better scan of the original 'classic' schematic and it 
seems to no longer be at that location; any chance it's still available 
somewhere?

TIA,

m
  ----- Original Message ----- 
  From: you got me 
  To: [email protected] 
  Sent: Friday, July 29, 2022 11:23 PM
  Subject: Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD


  The job you did must have taken a loooooooooooooooooooooong time. Perhaps 
some people will be able to make a M100 kit in time for the 40th anniversary. 
Thank you for your hard work!


  You were saying that the schematics you had access to were hard to read? 
Years ago I made a scan of the schematic in what I considered to be 'high 
definition'. You may want to take a look at it.


  TRS-80 Model 100 Main PCB Schematic (from Tech Ref Manual).jpg


------------------------------------------------------------------------------

  From: M100 <[email protected]> on behalf of Henner Zeller 
<[email protected]>
  Sent: Saturday, July 30, 2022 2:11 AM
  To: [email protected] <[email protected]>
  Subject: [M100] TRS-80 Model 100 schematic transcribed to KiCAD 

  Hi,

  I recently got a TRS-80 Model 100 and for fixing the the main-board I
  poured over various scans of the original schematic found on
  archive.org; and while it is great that these exist, the original
  schematic is still somewhat hard to read, so I decided to transcribe
  them to a modern schematic format - KiCAD

  I put the schema and symbols file as well as a generated PDF on github
  https://github.com/hzeller/trs80-100-schematic

  Status: Transcribed the full main-board (not the LCD board). All BOM
  entries (number+value) match with the list found in the documentation,
  all pin-assignments are accurate. Even deduced some values that are
  missing in the schematic (R162, 100Ohm discharging C78 in the reset
  circuit, as well as the designator for the 10n capacitor near the
  primary in the power supply .. C62). Schematic passes electrical rule
  check, so at least there are no obvious mistakes in there.

  I tried to keep the original layout as much as possible for easy
  recognition, but did slight changes to improve readability.
  For instance, I added a gap between the 'analog' and 'digital' part so
  that it is possible to print out on two sheets and glue together
  without losing content (or simply folding a large print-out without
  damaging important stuff). Also using IEC resistor symbols for
  readability and changed capacitor units where nanofarad is better
  (3300pF -> 3.3nF; 0.047μF -> 47nF); they didn't seem to use 'Nano'
  back in the day. Renamed some signals to be more useful, so `Ⓐ*` is
  now `RDRW*`. Used color encoding for the different buses on the system
  to easier see what is going on at a glance.

  If you find any mistakes (I am sure I missed something), please file
  an issue in the github's issue tracker.

  Cheers,
    Henner.

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