TRS-80 News

Some items I have on eBay to support the site ...

Books

Software

GrumpyX has kindly provide an issue of the opular Computing Newsletter

Title:Popular Computing NewsletterPublisher:Popular Computing IncYear:1978Size:1,062,862Pages:16OCRed:YesNotes:1978-12

GrumpyX has kindly provide a whole bunch of Radio Shack related scans ...

Title:Product Flyer - Carry In Service ContractPublisher:Radio ShackYear:1979Size:61,313Pages:1OCRed:Yes

Title:Product Flyer - Cobol Development System Model IIPublisher:Radio ShackYear:19xxSize:209,970Pages:4OCRed:YesNotes:26-4703

Title:Product Flyer - Fortran Development System Model IIPublisher:Radio ShackYear:19xxSize:247,816Pages:4OCRed:YesNotes:26-4701

Title:Product Flyer - Model II LeasingPublisher:A and A FinancialYear:19xxSize:827,162Pages:2OCRed:Yes

Title:Product Flyer - Network IPublisher:Radio ShackYear:19xxSize:433,883Pages:2OCRed:YesNotes:26-1210

Title:Radio Shack TRS-80 Software LibraryPublisher:Radio ShackYear:19xxSize:57,940Pages:1OCRed:YesNotes:Introduction to BASIC Part I / 26-2150

Title:Radio Shack TRS-80 Update 1978-02Publisher:TandyYear:1978Size:475,923Pages:4OCRed:YesNotes:07-05-1978

Title:Radio Shack TRS-80 Update 1978-03Publisher:TandyYear:1978Size:239,398Pages:2OCRed:YesNotes:08-10-1978

Title:Radio Shack TRS-80 Update 1979-09Publisher:TandyYear:1979Size:533,328Pages:4OCRed:YesNotes:09-28-1979

Title:Radio Shack TRS-80 Update 1979-10Publisher:TandyYear:1979Size:205,569Pages:2OCRed:YesNotes:10-16-1979

Title:Radio Shack TRS-80 Update 1979-11Publisher:TandyYear:1979Size:206,632Pages:2OCRed:YesNotes:10-31-1979

Title:Radio Shack TRS-80 Update 1979-12Publisher:TandyYear:1979Size:473,357Pages:6OCRed:YesNotes:11-15-1979

Title:Radio Shack TRS-80 Update 1979-13Publisher:TandyYear:1979Size:210,533Pages:2OCRed:YesNotes:12-03-1979

Title:Radio Shack TRS-80 Update 1979-14Publisher:TandyYear:1979Size:310,611Pages:4OCRed:YesNotes:12-31-1979

Title:Radio Shack TRS-80 Update 1980-04Publisher:TandyYear:1980Size:147,613Pages:2OCRed:YesNotes:02-01-1980

Title:Radio Shack TRS-80 Update 1980-05Publisher:TandyYear:1980Size:83,878Pages:1OCRed:YesNotes:02-04-1980

Title:Radio Shack TRS-80 Update 1980-09Publisher:TandyYear:1980Size:372,188Pages:4OCRed:YesNotes:04-02-1980

Title:Radio Shack TRS-80 Update 1980-10Publisher:TandyYear:1980Size:285,200Pages:4OCRed:YesNotes:04-07-1980

Title:Radio Shack TRS-80 Update 1980-11Publisher:TandyYear:1980Size:337,548Pages:4OCRed:YesNotes:04-29-1980

Title:Radio Shack TRS-80 Update 1980-13Publisher:TandyYear:1980Size:386,403Pages:4OCRed:YesNotes:06-27-1980

Title:Radio Shack TRS-80 Update 1980-14Publisher:TandyYear:1980Size:341,911Pages:4OCRed:YesNotes:07-07-1980

Title:Radio Shack TRS-80 Update 1980-16Publisher:TandyYear:1980Size:611,867Pages:8OCRed:YesNotes:09-01-1980

Title:Radio Shack TRS-80 Update 1980-17Publisher:TandyYear:1980Size:378,338Pages:4OCRed:YesNotes:09-12-1980

Title:Radio Shack TRS-80 Update 1980-18Publisher:TandyYear:1980Size:595,581Pages:8OCRed:YesNotes:10-09-1980

Title:Radio Shack TRS-80 Update 1980-20Publisher:TandyYear:1980Size:338,670Pages:4OCRed:YesNotes:11-26-1980

Title:Radio Shack TRS-80 Update 1980-22Publisher:TandyYear:1980Size:722,752Pages:8OCRed:YesNotes:12-24-1980

Title:Radio Shack TRS-80 Update 1981-01Publisher:TandyYear:1981Size:312,942Pages:4OCRed:YesNotes:01-14-1981

Title:Radio Shack TRS-80 Update 1981-02Publisher:TandyYear:1981Size:166,877Pages:2OCRed:YesNotes:01-21-1981

Title:Radio Shack TRS-80 Update 1981-03Publisher:TandyYear:1981Size:358,883Pages:4OCRed:YesNotes:02-03-1981

Title:Radio Shack TRS-80 Update 1981-06Publisher:TandyYear:1981Size:373,943Pages:4OCRed:YesNotes:04-01-1981

Title:Radio Shack TRS-80 Update 1981-07Publisher:TandyYear:1981Size:357,870Pages:4OCRed:YesNotes:04-23-1981

Title:Radio Shack TRS-80 Update 1981-08Publisher:TandyYear:1981Size:379,310Pages:4OCRed:YesNotes:05-08-1981

Title:Radio Shack TRS-80 Update 1981-09Publisher:TandyYear:1981Size:378,102Pages:4OCRed:YesNotes:05-18-1981

Title:Radio Shack TRS-80 Update 1981-10Publisher:TandyYear:1981Size:329,809Pages:4OCRed:YesNotes:06-03-1981

Title:Radio Shack TRS-80 Update 1981-11Publisher:TandyYear:1981Size:82,093Pages:2OCRed:YesNotes:06-15-1981

Title:Radio Shack TRS-80 Update 1981-12Publisher:TandyYear:1981Size:60,460Pages:2OCRed:YesNotes:06-24-1981

Title:Radio Shack TRS-80 Update 1981-13Publisher:TandyYear:1981Size:179,064Pages:2OCRed:YesNotes:06-29-1981

Title:Radio Shack TRS-80 Update 1981-14Publisher:TandyYear:1981Size:135,527Pages:2OCRed:YesNotes:07-08-1981

Title:Radio Shack TRS-80 Update 1981-18Publisher:TandyYear:1981Size:181,324Pages:2OCRed:YesNotes:08-12-1981

Title:Radio Shack TRS-80 Update 1981-21Publisher:TandyYear:1981Size:191,934Pages:2OCRed:YesNotes:09-08-1981

Title:Radio Shack TRS-80 Update 1981-22Publisher:TandyYear:1981Size:212,757Pages:2OCRed:YesNotes:09-29-1981

Title:Radio Shack TRS-80 Update 1981-23Publisher:TandyYear:1981Size:212,395Pages:2OCRed:YesNotes:10-09-1981

Title:Radio Shack TRS-80 Update 1981-27Publisher:TandyYear:1981Size:211,238Pages:2OCRed:YesNotes:11-06-1981

Title:Radio Shack TRS-80 Update 1981-31Publisher:TandyYear:1981Size:228,069Pages:2OCRed:YesNotes:12-18-1981

Title:Radio Shack TRS-80 Update 1982-01Publisher:TandyYear:1982Size:267,637Pages:2OCRed:YesNotes:01-07-1982

Title:Radio Shack TRS-80 Update 1982-02Publisher:TandyYear:1982Size:226,611Pages:2OCRed:YesNotes:01-21-1982

Title:Radio Shack TRS-80 Update 1982-03Publisher:TandyYear:1982Size:225,192Pages:2OCRed:YesNotes:02-22-1982

Title:Radio Shack TRS-80 Update 1982-04Publisher:TandyYear:1982Size:292,951Pages:3OCRed:YesNotes:03-08-1982

Title:Radio Shack TRS-80 Update 1982-05Publisher:TandyYear:1982Size:540,253Pages:5OCRed:YesNotes:04-06-1982

Title:Radio Shack TRS-80 Update 1982-06Publisher:TandyYear:1982Size:386,402Pages:4OCRed:YesNotes:04-27-1982

Title:Radio Shack TRS-80 Update 1982-07Publisher:TandyYear:1982Size:456,079Pages:4OCRed:YesNotes:05-24-1982

Title:Support Group ListPublisher:TandyYear:1983Size:203,572Pages:2OCRed:Yes

Title:Thank You for Tampa Computer ShowPublisher:TandyYear:1980Size:257,516Pages:1OCRed:Yes

Title:TRS-80 Merchandising Memo 81-09 [700 Series Software Items]Publisher:TandyYear:1981Size:99,584Pages:1OCRed:YesNotes:700 Series Software Items

Title:TRS-80 System Selection GuidePublisher:TandyYear:19xxSize:60,836Pages:1OCRed:Yes

• Tuc has TRS-IO++ fully assembled boards in stock and ready for immediate shipping. Visit his site for more information.

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• Dusty has TRS-80 Model I keyboards based on MX keys for sale. Visit his DustysVintageWorkshop ebay store.

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• KiwiSinceBirth has pointed out that his Model I and Model III updated ROMs come with 16 pre-built configurations as well as source code, for those daunted by the compilation process

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• Irwin Burton has written two new TRS-80 Model III programs - NAMEIT and PWD. NameIt allows for all characters to be in a LDOS disk label and PWD (like the unix command) will give you a quick update of what disk is mounted in a drive number. Source is included.

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• The next TRS-80 Trash Talk (#47!) is scheduled for Saturday, February 21, 2026 at 6:00PM Pacific Daylight Time. To watch, visit https://www.youtube.com/@TRS80TrashTalk. If you want to participate, reach out for the zoom link.

KiwiSinceBirth has posted updates to his compilable source file for the Model I/III ROM

He has a traditional Model I Level 2 BASIC ROM and Model III Level 2 BASIC ROM which have comments and which can be compiled into a workable ROM. His source differs from a standard disassembly in the following ways

• Replaced all disassembler generated labels with meaningful labels.
• Ensured all jumps (JR and JP) reference valid code labels.
• Replaced all $3xxx hardware references with .EQU definitions.
• Replaced all $4xxx buffer references with .EQU definitions.
• Replaced all $xx byte references with appropriate decimal or ascii values, and/or .EQU definitions.
• Replaced all generated op-code with Byte .DB .DW definitions for DataTables/Text/Constants/Etc
• Added code documentation from various sources at the code block / function level.
• Replaced incorrect op-codes, where Better Else "Trick" was used.

These ROMs can also be somewhat customized as follows:

He has also developed an enhanced ROM for both machines which have slightly broken compatibility, but which otherwise include new support, features, and some bug fixes

To make room for all this, cassette support has been removed.

Additionally, you can now download pre-built binary images for most common configurations. There are 16 variants. Hr did this to make it easier to use, no assembly required, no defines to understand, just choose the ROM that makes sense. It also means the vanilla configurations can be compared against official roms, to check for binary compatibility. This build process is automated by GITHub anytime a change is made, it will assemble and publish a new release.

• Dick Smith System 80 (Official)
• Dick Smith System 80 FreHd Patched
• Dick Smith System 80 Patched
• Model I Rev 1.2 (Official)
• Model I Rev 1.3 - FreHD Patched
• Model I Rev 1.3 - Patched
• Model I Rev 1.3 (Official)
• Model I Rev 1.4 (Enhanced 50Hz)
• Model I Rev 1.4 (Enhanced)
• Model I Rev 1.4 (Enhanced)
• Model III - FreHd Patched
• Model III - FreHd Patched 50Hz
• Model III - Patched
• Model III - Patched 50Hz
• Model III (Official)
• System 80 Rev 1.4 (Enhanced)

Visit his site here.

George and Peter Phillips have updated their awesome TRS80GP emulator to v2.5.6. Changes are:

New Features:

• Added "feed" and "delay" script commands.
• Backtrace now annotated with labels when they are available.
• Directly loaded Model 1 and 3 BASIC programs now convert ^ to [
• Disk viewer can be used to modify sector data.
• Gendon character ROM available for model 1 via -charrom :gendon
• Green Thumb emulation.
• IMD disk image saves blank tracks as empty records, allows HxC 0x80 modes.
• Implemented "load" and "run" script commands.
• Printer menu options for 80 and 132 column fixed-width printing.
• Supermem (-mem supermem) and X-MEM/80 support for Model 1 (-mem xmem80).

Bug Fixes:

• 6809 subtract/compare operations no longer modify the half-carry flag.
• Add delay to FDC Restore to fix Arranger II adding disks.
• Disk viewer/disk summary works correctly for hard drives using sector ID ranges 1..n
• Fixed Mac context menu
• Fixed Mac debug disassembly window for some processors.
• Improved IM 0 mode for Model I allowing TPM to format a diskette.
• Memory views no longer wrap around to address 0; it was too confusing.
• Model 12, etc. back to immediately reacting to bank swap (port $A8).
• RS-232 transmit interrupt asserted at when RS-232 reset.
• Use only 4 bits of FreHD commands like the real FreHD.

You can download it at http://48k.ca/trs80gp.html

The next TRS-80 Trash Talk live show is January 16, 2026 at 6:00PM Pacific Daylight Time / 9:00PM Eastern Daylight Time!

You can watch on the TRS-80 Trash Talk channel: https://www.youtube.com/channel/UCXkGugvdCkpkMDylVQb9gfg

If you want to participate in the live zoom session, reach out to trs80trashtalk at gmail dot com for information.

Title:Ham Package IPublisher:Instant SoftwareYear:1978Size:2,504,157Pages:12OCRed:Yes*

Title:Electronics IPublisher:Rick Morel - Instant SoftwareYear:1978Size:4,185,191Pages:22OCRed:Yes*

Ian Mavric was kind enough to send over some missig items! Thank you, Ian!

Paul Hopkins was kind enough to send over Key Commander, one of the known missing files!

The manual can be downloaded Here

And the CAS/WAV image can be downloaded Here

Thank you, Paul!

Happy New Year everyone!

To make linking easier, I have added clipboard icons to the Hardware, Software, and Service Manual pages.

The SSL certificate for www.trs-80.org has been purchased and applied, so related security warnings should have stopped.

TRSDOS v1.3 and 2.3 have been disassembled and commented.

The main page for TRSDOS v2.3 for the Model I can be found here.

The main page for TRSDOS v1.3 for the Model III can be found here.

NEWDOS/80 v2.0 for the Model I has been disassembled, with most of the heavy lifting done by Claude AI, with help from Gemini and Grok. They all definitely have their strengths and weakenesses.

The main page can be found here.

I have also created a main-menu entry for all disassemblies, to make them easier to get to. That can be found on the navbar, or here.

Shawn Sijnstra has released v18 of this Infocom Adventure Interpreter line. His changelog:

• Code optimisation for speed and size including init, bwdcopy, fwdcopy, tokenize, inibuf, find_word, next_token, llf
• Rewrote all core code to assume auto-increment of ZPC to improve speed and size
• Bugfix: handle auto wrapped line followed by immediate line feed
• Additional space freed to allow for more game cache
• Memory map reshuffled to reduce disk size. CP/M version 900+ bytes smaller freeing up extra disk space

The official site can be found at:

• Model I Version
• Model III Version
• Model 4 Version

Jens Guenther has updated his Windows/Linux fork of the SDLTRS Emulator to v1.2.34

Changelog:

• Added Holmes VID-80 (VX-3) support for TRS-80 Model III.
• Added 48 KB extended memory for Holmes VID-80 (VX-3).
• Added 256/512/768/1024 KB for Alpha Technology SuperMem.
• Added X-MEM/80 (Michael Wessel) 16K page Model I memory extension.
• Added printer type for text only output.
• Fixed LNW80 Model II banking and 80x24 text mode support.
• Fixed some bugs and internal improvements.

You download the source and binaries here. This download includes the required SDL2.dll

The official site can be found at https://gitlab.com/jengun/sdltrs

Lawrence Kesteloot has updated his TRS80Tool to v2.8.2. Changelog is:

Fix a bug in the display of file sizes in the dir command.

You can download a ZIP with the Windows, Mac, Linux, and Source combined right here.

Lawrence has also updated his online TRS-80 Assembly Language IDE, found at https://www.my-trs-80.com/ide/. Changelog is:

• The “File” menu has a new “Play Cassette Audio” command to play the assembled program as an audio sound. Connect your computer’s audio to a real machine and use the SYSTEM BASIC command to start the load.
• The “Edit” menu has a new “Auto-complete on Tab” option to set whether the Tab key accepts the auto-completion suggestion.
• The “View” menu has a new “Show Statistics” option that displays code and data statistics for the whole program and the current selection.
• The “View” menu has a new “Screen Size” option to change the size of the screen, in case you want more room for the text editor.
• The “Debug” menu has a new “Inspectors” sub-menu to show a Floppy Disk Controller inspector.
• The “Help” menu has a new “About” option to show the IDE’s version and release date.

If you sent in a disk request which was not processed, you have my apologies. As part of the site redesign, I seem to have dropped the perl script which actually sent the disk request form in! If you emailed me, it was processed; but if you silently sent in the form and that's it ... it wasn't. I have fixed the form so it should submit. If you requested disks and did not get them, please fill out the form again.

You can download it from http://TRS-80.org.uk/ or an OCR'd version here.

Issue Information:

Issue Summary:

George Phillips discusses Bart Jeroen Hemstra’s winning competition entry. Ian Mavric shows how to downgrade a Model 1 to Level 1, has a report of the 2025 Tandy Assembly and takes a look at Model 2000 hardware add-ons with part 2 of his series. Vince Otten has part 4 of his ‘Power of the ROM’ articles and also looks at early PASCAL compilers for the Model 1. E.T. Fonehume has a BASIC one-liner screen-saver, for a seasonal snowflake. Pascal Holdry has news of his latest, fantastic, re-engineering hardware tasks. There’s a quick look back to the early 1980’s in ‘The Way We Were’. Also, there’s a round-up of a few U.K. Ebay bargains, a maze puzzle just for fun and finally, ‘Surfin the Net’ comes up with an ‘all new’ Model 1 motherboard. 84 pages of pure Tandy joy!

Table of Contents

I wanted to make it easier for people to be able to refer to specific portions of the site, so I have added CSS and Javascript that will put a little clipboard up on headers. If you click the clipboard, the URL for that specific header will be copied to your clipboard. Thank you Gemini for the code!

The commented/explained disassembly of BACKUP/CMD from Model I TRSDOS v2.3 can be found here and TAPEDISK/CMD can be found here.

Amardeep Chana has written up step-by-step instructions to modify a Model I to run much cooler and more reliably. It involves modifying the system to no longer need the +/-12V to power the RAM, focusing solely on 5V.

You can download the step-by-step guide here.

The Easter Egg page page has been updated with a reverse engineering of Randy Cook's secret screen from TRSDOS v2.x. Thanks to George Philips and absolutely no thanks to Gemini who halucinated an elaborate routine that didn't exist!

Thank you to everyone that has been reporting in with questions and issues!

And special thanks to Ven Reddy who pointed out that when I moved off of WordPress I lost the Site Search function. I personally consider the site too unwieldy and too hard to find anything, and I wrote it - so I can imagine what everyone else goes through. So the loss of site search was a big loss. The site search page is now present on the navbar but can be found here as well.

If anyone has any better ideas as to how to organize the navigation or make it easier to find subpages and content, please let me know.

In other updates, I have been working on the disassembly pages trying to add more information to the input/output portions. Right now it's in the form of adding bit tables to show all the options and explanations within each comment. Also, as of last night, the disassemblies are "mobile friendly".

I think the site redesign is now done. Some pages have had major rewrites (all thanks to AI) like the Missing Software page, and the search pages, but by this point all pages are using consistent CSS which has been minimized.

While I was at it, I tried to augment the magazine pages to all include the table of contents (where they existed).

If you still see any formatting errors or issues, let me know.

Today was the first time I ran into what Ian has run into for a while ... unreadable Radio Shack brand disks. I previously had good luck with them, but today I received two different sets of disks to read. One was Radio Shack only and one was Radio Shack and Storage Media.

With almost no exceptions, I was unable to read the Radio Shack disks from both sets. I had thought a bunch of Storage Media disks were also bad, but upon trying to second set, it dawned on me to try reading without introducing any Radio Shack disks into the process. Once I did that, all Storage Media disks read without issue.

I wonder if we have hit some sort of magic timeframe whereby Radio Shacks are now no longer viable. I mean, its been over 40 years and its a miracle that any disks can be read ... but perhaps Radio Shack disks are now past their time?

A new page for all available TRS-80 upgrades and add-ons as been added. The various associated information is still present wherever it is on the site, but this page attempts to consolidate all of the offerings. If there is any missing or incorrect information, please let me know. You can see the new page here.

Also, I have updated the TRSDOS v1.3 Zaps page to include explanations as to what each patch does along with jumps into the various disassemblies.

KiwiSinceBirth has posted his compilable source file for the Model III ROM

Main Features

• Fully Compilable Source Code for Model III Level 2 14KB ROMS
• Several optional patches have been included via #DEFINE
• Based on ROM A = 9639, ROM B = 407C, ROM C = 2EF8

Build Options

There are several DEFINE's that can be set in the code (very start) to enable certain features.

• #DEFINE VIDEO50 - Enable 50Hz Video Support (Affects RTC)
• #DEFINE FREHDBT - Enables the FreHD auto boot ROM feature, ie load fre HD at start
• #DEFINE BUGFIX27 - Fix Bug 27 - 06CCH - Basic Entry Point
• #DEFINE BUGFIX28 - Fix Bug 28 - 034BH - Stack Initialisation Problem
• #DEFINE BUGFIX30 - Fix Bug 30 - 034BH - 32 char Mode, Incompatible Model 1 code
• #DEFINE BUGFIX40 - Fix Bug 40 - 05D1H - Broken "RON" Printer Status Routine
• #DEFINE SIZE16K - Will pad the end of the rom with $FF to 16KB size. useful if want to append multiple ROM images for used in large 16K paged rom
• #DEFINE DONTEND - Disable .END directive if #INCLUDEing the source inside another file

Visit his site here.

When Matthew Reed passed, and asked me to host his sites, he gave me wordpress pages converted to HTML. That was the way to do it, since WordPress works off of a bunch of PHP code on the back and and a large database - not easily movable.

The process of making that HTML usable, though, was challenging; particularly since the HTML was just a frozen moment-in-time of the WordPress, with all the stats bars ('most read articles', 'associated articles', etc) locked in place, and all pointing to directories instead of .html files.

Since we are all mortal, I thought about that and decided to convert TRS-80 away from WordPress. It will make maintaining site much easier, for sure.

The most significant improvement is in terms of screen width - no longer wedged into 800 pixels for no valid reason. The 3 search page results now also span the width, making things a lot less crushed. On the mobile side, those pages scroll, and most of the HTML seems to be working great on the smaller screens. Also, "Click to Enlarge", "Click to Download", and "Click to Email" are all inserted by CSS automatically so you know what clicking on something might afford.

If you come up with any 404 errors, or any really-off formatting, or have any usable suggestions, please let me know.

Larry Fosdick has come across a cache of DOSPlus News Information Centers. Thank you, Larry!

Title:DOSPlus News Information Center 82-01-02Publisher:Micro Systems SoftwareYear:1982Size:8,318,607Pages:20OCRed:Yes*Notes:Set 2

Title:DOSPlus News Information Center 82-05-06Publisher:Micro Systems SoftwareYear:1982Size:12,336,303Pages:36OCRed:Yes*Notes:Set 2

Title:DOSPlus News Information Center 82-07-08Publisher:Micro Systems SoftwareYear:1982Size:14,950,795Pages:36OCRed:Yes*Notes:Set 2

Title:DOSPlus News Information Center 82-09-10Publisher:Micro Systems SoftwareYear:1982Size:10,226,736Pages:40OCRed:Yes*Notes:Set 2

Title:DOSPlus News Information Center 83-SummerPublisher:Micro Systems SoftwareYear:1983Size:23,459,217Pages:43OCRed:Yes*Notes:Set 2

The next TRS-80 Trash Talk live show is November 1, 2025 at 6:00PM Pacific Daylight Time / 3:00PM Eastern Daylight Time!

You can watch on the TRS-80 Trash Talk channel: https://www.youtube.com/channel/UCXkGugvdCkpkMDylVQb9gfg

If you want to participate in the live zoom session, reach out to trs80trashtalk at gmail dot com for information.

KiwiSinceBirth has released v2.0a of his redesigned Model I motherboard. He reports the following changes:

This project is an upgraded / evolved TRS-80 Model 1 main board replacement. It was designed to provide a reliable, compact, and modern replacement, removing some limitations of the original 1970's product, while still remaining faithful to the original technology (i.e. no emulation)

v2.0a provides significant improvements in video, not only does it use dual port RAM for snow free video, but it changes the video sync generation circuit bringing back the picture adjustment controls not present in V1. Also supported is software switchable fonts, for alternate languages or other graphics. Other major features added to the board include an audio amplifier for a small speaker (which can be mounted on the board), Alpha Joystick port compatible with most software, and ability to mount a modern clock oscillator. Have added about 10 new config jumpers/settings in support of new features. V1 is still fully supported including a separate build guide. Not forgetting Supermem bank RAM and internal FreHD

>New Features

• Dual port video SRAM, reducing contention (snow) issues with shared CPU access.
• Onboard Audio amplifier utilising small class D module, with space for PCB speaker
• Alpha Joystick port with header to connect 9 Pin DB9 Connector
• Changed crystal oscillator to parallel resonant circuit based on 74HCU04 chip, which is pin compatible with a Full Can (DIP14) oscillator.
• New Video sync generation circuit, including Horizontal and Vertical Position.
• Improved support for RGBtoHDMI by exposing HSYNC on Video DIN socket
• Added Tim Halloran's no-chip VBLANK modification, for improved video updating.
• Added Jumper (JP16) to allow main Reset button to function as full CPU reset.
• Can configure either RAM or ROM to occupy the 12kB to 14kB address space in memory.
• Added support for EEPROM in circuit writing (requires software support).

Changed Features

• The Video DIN socket now has Jumper (JP19) to disable external power
• Added PCB reset button (SW11) to allow full reset during diagnostics
• CPU speedup offer fast speed as 5.3 (default 3.55) mhz via jumper (JP17)
• Added Power LED indicator (D1) near to the main power switch.
• Fixed issue with TEST signal immediately disconnecting CPU from BUS - Credit Marcel Erz
• Fixed Issue with Bus control for interrupt Mode 0 and 2 where external device places data on bus
• Added (back) software character set control (Port FF Bit 7), as per JP board.
• Changed meaning of SW10-SW13. Now ON => Logic 1, and OFF => 0 (rather than reverse)
• RAM is configurable from $48k (default) down to 16k for compatability with external RAM.

Minor Improvements

• Moved main 10.6Mhz oscillator to central location, shorter signal paths.
• CPU clock speed selector flip-flop (Z63a) clocked at slowest rate.
• JP10 (and related circuit) used for video frequency was removed.
• Inputs of spare gates are now tied to GND or VCC, with easy trace cuts for future use.
• Added resistor pull-ups on address, data, and control busses, for CMOS stability.
• Added resistor pull-ups on keyboard, prevent issues when no keyboard attached.
• Provided ability to use spare IO pins (CAS and MUX) on IO expansion.
• Moved main power switch (SW1) and socket (J11) closer to other ports, better clearance
• Added several M3 mounting holes for internal expansion board mounting
• Improved (more modern) footprints for C19, C70, Q1, Q2, CR4.
• Replaced several discrete resistors with small resistor packs.
• Fixed multiple issues with small via's and thermal reliefs on power rails
• Main power Capacitor C101 now has more space for horizontal mounting.
• Improved silkscreen for component identification, and configuration options
• Improved component identification in Bill of Materials
• Major improvement in the Schematic diagram quality.
• Many component designators have changed from V1, so some V1 docs may not be accurate
• Added testpoints to support 3 signals required by SuperMem
• Changed main power capacitor C11 to 470Uf after testing from MSly
• Changed main power switch to discharge C11 (using 100R R14) when switched off
• Keyboard resistor pack RN5 corrected to pull down keyboard data lines.
• Corrections to Bill of Materials, and silkscreen fixes and improvements.

You can find all the information, as well as downloads for the BOM and circuit board, at github.com/kiwisincebirth/TRS-80-MODEL-1-K/tree/main

Well, the first pass of the AI conversion did an OK job, even if it took about a month due to token limits. The problem is that it created 1500 classes because of the number of sessions that had to be used. Instead of it being able to consistently review pages and apply consistent code, even when instructed to re-use old code, it didn't do a great job.

So I need to make another pass. I have developed, with AI's help, three main types of code sections - general, columnar, and images. As I move page to page, I have those codes updated as needed. This should bring consistency to the site.

Some of the things about the new design that I absolutely love, is that a simple CSS class added to a catalog entry, email address, or clickable image, just adds a note telling you what you can do with that. This is something I would have used JQUERY for in the past, but CSS3 is pretty awesome! Examples are the little caption on the pictures below; automatically added by CSS.

Anyway, the AI page pass left me with 1500+ CSS entries, and those need to get culled. Well, most of them. It turns out that the new search pages require 450 CSS entries! They are kind of beautiful, so I'm going to leave those alone.

For the rest of the pages, I had Gemini write some Visual BASIC Code to parse every html file, extract every class used, and come up with a display that would show me the class, the code, and the files which use it. I also had to have it let me know about dependencies after a particularly disasterous attempt to globally update the code.

This is a sample of the output.

Here, there is a class used by only 1 page. In this case, it's because its a typo. But putting that aside, it is my clue as to the next page to edit. I then go through and update the page to use the new classes.

Once that page (or pages) are done, I use WildEdit to search the entire tree for the class.

If it shows no changes made, then I can delete the CSS.

I also had a button prepared that would output the "good" and "bad" css. If I get tired of editing specific pages, but still want to make progress, I use WildEdit to find entries that are on the "bad" page. If there are no results, I can just strike that CSS entry.

So that's what's going on now ....

But as of this point, v1 CSS is pretty much gone, so if you see a page (or table) that is broken, let me know!

Update: Claimed

A site visitor (and very frequent contributor) has multiple Model I components that he would like to give away by local pickup only in the Norfolk, Nebraska area.

He lists:

• two monitors
• two expansion interfaces
• three keyboard units (one not working)
• a few floppy drives (condition unknown, but worked a few years ago)
• several DOS manuals, books, and newsletters

If you are interested in picking up that stuff, please contact me and I will pass on your interest.

Between Claude AI and Gemini Pro (but definitely not Gemini Flash), the web site has been updated to new CSS. I have moved prior news into the "old news" pages because WordPress would require me to update each news item individually otherwise.

You can see 2025 news here.

There might be broken CSS when I kill the old CSS. I still have work to do though. Since AI sessions can only be so long, each new session required me to feed in the CSS to date, and I instructed it to re-use as much CSS as it could. Despite that, over 650 new CSS definitions were created; so much for site consistency.