Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[MikeS]

It is indeed! Thank you!

 Original Message - 
  From: Henner Zeller 
  To: m...@bitchin100.com 
  Sent: Sunday, November 13, 2022 7:48 PM
  Subject: Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD


  On Sun, 13 Nov 2022 at 16:43, MikeS  wrote:

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?


  Looks like it is here  
https://archive.org/details/trs-80-model-100-main-pcb-schematic-from-tech-ref-manual

TIA,

m
  - Original Message - 
  From: you got me 
  To: m...@bitchin100.com 
  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 loong 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  on behalf of Henner Zeller 

  Sent: Saturday, July 30, 2022 2:11 AM
  To: m100@lists.bitchin100.com 
  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.

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[Henner Zeller]

On Sun, 13 Nov 2022 at 16:43, MikeS  wrote:

> 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?
>

Looks like it is here
https://archive.org/details/trs-80-model-100-main-pcb-schematic-from-tech-ref-manual

>
> TIA,
>
> m
>
> - Original Message -
> *From:* you got me 
> *To:* m...@bitchin100.com
> *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 loong 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
> <https://1drv.ms/u/s!AgRHXuUu57Cegkh7fKaiso-Res2H?e=PEAoZk>
> --
> *From:* M100  on behalf of Henner
> Zeller 
> *Sent:* Saturday, July 30, 2022 2:11 AM
> *To:* m100@lists.bitchin100.com 
> *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.
>
>

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[MikeS]

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: m...@bitchin100.com 
  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 loong 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  on behalf of Henner Zeller 

  Sent: Saturday, July 30, 2022 2:11 AM
  To: m100@lists.bitchin100.com 
  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.

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[Henner Zeller]

Hi,


> [...]
> 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.
>

In the meantime I've updated some small errors (typos in hard-to-read
pin-numbers discovered when cross-checking with the chip datasheets), and
updated a bunch of annotations, such as RC filter calculations, updated the
keyboard matrix (which had some wrong key-assignments in the original
schematic), fixed switch-positions in the modem section or annotate which
is that resistor that goes across the board in a shrink-tubing...

Also, more improvements to readability; while at first I mostly had the
arrangement in the same way as the original schematic did it, now I've
updated some sections for more readability. In particular the convoluted
way the VB rail was wired up or the flow of the reset circuit was somewhat
hard to read is now much improved (I think).

Updated schematic and PDF (by click on the image) on the same repo
https://github.com/hzeller/trs80-100-schematic

Cheers,
  Henner.

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD (Henner Zeller)

[Charles Hudson]

May I add my thanks for undertaking this task:  It is a marvelous piece of
work and greatly appreciated.

-CH-


Virus-free.
www.avg.com

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[Brian Brindle]

Fantastic work! Thank you for sharing!

Brian


On Fri, Jul 29, 2022 at 10:12 PM Henner Zeller  wrote:

> 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.
>

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[Henner Zeller]

>
>
> Ohh, that is a very nice scan indeed, nicely readable! I didn't find it
> coming up in a search,  my sources were the ones I listed in the README.
> The URL you supplied looks a bit ephemeral - is there a stable URL
> somewhere (Maybe upload it to archive.org) ? I'd also like to link it in
> the README if you don't mind.
>

Ah, found it:
https://archive.org/details/trs-80-model-100-main-pcb-schematic-from-tech-ref-manual/
Added the link to the README.

-h

> TRS-80 Model 100 Main PCB Schematic (from Tech Ref Manual).jpg
>> <https://1drv.ms/u/s!AgRHXuUu57Cegkh7fKaiso-Res2H?e=PEAoZk>
>> --
>> *From:* M100  on behalf of Henner
>> Zeller 
>> *Sent:* Saturday, July 30, 2022 2:11 AM
>> *To:* m100@lists.bitchin100.com 
>> *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.
>>
>

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[Brian White]

This is wonderful, thank you!

bkw

On Fri, Jul 29, 2022, 10:12 PM Henner Zeller  wrote:

> 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.
>

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[Scott McDonnell]

Maybe a good thing you never found it! You might not have done the Kicad 
schematic.Great work and thanks so much for sharing it!
 Original message From: Henner Zeller  Date: 
7/30/22  12:51 AM  (GMT-05:00) To: m...@bitchin100.com Subject: Re: [M100] 
TRS-80 Model 100 schematic transcribed to KiCAD On Fri, 29 Jul 2022 at 21:23, 
you got me  wrote:






The job you did must have taken a loong time. Yes, about 
two weeks working on it in the evenings. I started with the power-supply 
section, but then I just kept going. Time-consuming was to create a bunch of 
new symbols to match the ones in the original schematic in pin-out to keep the 
same visual flow.I am happy about the result.Perhaps some people will be able 
to make a M100 kit in time for the 40th anniversary. Thank you for your hard 
work!This seems to be in reach. I do consider using the scans of the PCB to 
maybe, import these as images of the copper, assign the nets and see if this is 
a good way to re-create the PCB electronically. Maybe not as easy as the PCB 
image in the manual has the silk-screen on top of it - so some re-work 
required. For an actual re-build ... there are some parts that don't exist 
anymore (is the 80C85 still in production ?), and some that can be simplified 
(say the 4x8k modules which each are 4x2k with their four enable lines could be 
replaced with a single 32k static ram), and others could probably left 
unpopulated entirely (who needs a modem with a pulse dialler ?). Many parts of 
the era that don't exist anymore can be replaced with modern equivalents (40Hxx 
-> 74HCxx).




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'. Ohh, that is a very nice scan indeed, nicely readable! I didn't 
find it coming up in a search,  my sources were the ones I listed in the 
README.The URL you supplied looks a bit ephemeral - is there a stable URL 
somewhere (Maybe upload it to archive.org) ? I'd also like to link it in the 
README if you don't mind.Cheers,  Henner.TRS-80
 Model 100 Main PCB Schematic (from Tech Ref Manual).jpg




From: M100  on behalf of Henner Zeller 

Sent: Saturday, July 30, 2022 2:11 AM
To: m100@lists.bitchin100.com 
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.

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[Henner Zeller]

On Fri, 29 Jul 2022 at 21:23, you got me  wrote:

> The job you did must have taken a loong time.
>

Yes, about two weeks working on it in the evenings. I started with the
power-supply section, but then I just kept going. Time-consuming was to
create a bunch of new symbols to match the ones in the original schematic
in pin-out to keep the same visual flow.
I am happy about the result.

Perhaps some people will be able to make a M100 kit in time for the 40th
> anniversary. Thank you for your hard work!
>

This seems to be in reach.

I do consider using the scans of the PCB to maybe, import these as images
of the copper, assign the nets and see if this is a good way to re-create
the PCB electronically. Maybe not as easy as the PCB image in the manual
has the silk-screen on top of it - so some re-work required.

For an actual re-build ... there are some parts that don't exist anymore
(is the 80C85 still in production ?), and some that can be simplified (say
the 4x8k modules which each are 4x2k with their four enable lines could be
replaced with a single 32k static ram), and others could probably left
unpopulated entirely (who needs a modem with a pulse dialler ?). Many parts
of the era that don't exist anymore can be replaced with modern equivalents
(40Hxx -> 74HCxx).

>
> 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'.
>

Ohh, that is a very nice scan indeed, nicely readable! I didn't find it
coming up in a search,  my sources were the ones I listed in the README.
The URL you supplied looks a bit ephemeral - is there a stable URL
somewhere (Maybe upload it to archive.org) ? I'd also like to link it in
the README if you don't mind.

Cheers,
  Henner.

TRS-80 Model 100 Main PCB Schematic (from Tech Ref Manual).jpg
> <https://1drv.ms/u/s!AgRHXuUu57Cegkh7fKaiso-Res2H?e=PEAoZk>
> --
> *From:* M100  on behalf of Henner
> Zeller 
> *Sent:* Saturday, July 30, 2022 2:11 AM
> *To:* m100@lists.bitchin100.com 
> *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.
>

Re: [M100] TRS-80 Model 100 schematic transcribed to KiCAD

[you got me]

The job you did must have taken a loong 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.

<https://1drv.ms/u/s!AgRHXuUu57Cegkh7fKaiso-Res2H?e=PEAoZk>
[https://dsm01pap003files.storage.live.com/y4mIiYLUuV3CoTHeOGbYVHt__5OAVylr8Mk_9HDLIk_gK8378IY3rHYIcTpvSdnlf6Iz2AWUHz5_ZHnEuL0qI0nvO9eJmsj2YIvITNOWVE_GwhUsWUB0OVNh7lZ7011r_xt1Pj-AXDTP9Am756HGWraLl_9Bfs5pXs4E8P9ocoOTvo?width=200=150=center]
[https://res-2.cdn.office.net/assets/mail/file-icon/png/cloud_blue_16x16.png]TRS-80
 Model 100 Main PCB Schematic (from Tech Ref Manual).jpg


From: M100  on behalf of Henner Zeller 

Sent: Saturday, July 30, 2022 2:11 AM
To: m100@lists.bitchin100.com 
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.

[M100] TRS-80 Model 100 schematic transcribed to KiCAD

[Henner Zeller]

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.