TRS-80 Model I Documentation

The following documents were found from various locations on the web. I offer thanks to those that spent the time scanning these docs as it is a time consuming and thankless job.

There are several variations of these docs floating around the net, and it can be confusing knowing exactly what doc you need vs. what is yet another copy of the same manual you already downloaded elsewhere. Rather than offering all the duplicate files and extraneous stuff which most people really don't need, the purpose of this page is to offer the most complete and current versions of the docs (that I could find) which you do need, and with explanations as to why you care. If there's something you are looking for that isn't here, I may have it. Just contact me.

If you have a newer or better version of one of these documents, or a doc which you think should be added here, please let me know so I can update this archive.

Overview Manuals and BASIC Language Programming

• Information Guide For New Computer Owners (19xx)(Radio Shack)(pdf).zip
  • If you know nothing about your TRS-80 Computer, start with this manual.
• Level 1 Users Manual (1977)(David Lien)(pdf).zip
  • This is the BASIC programming reference manual for Level 1 BASIC computers only. It is not needed for Level II systems. Most people have Level II systems.
• Level II BASIC Reference Manual (1979)(Radio Shack)(pdf).zip
  • This is the Level II BASIC reference manual, needed for cassette based Model I computers with Level II BASIC, or when booting your disk based Model I into cassette BASIC (by holding down the BREAK key while powering up or pressing the RESET button). If you have a disk system and want to use Disk BASIC, see below.

Expansion Interface, Disk Drives, TRS-DOS, and Disk BASIC

• Expansion Interface Manual [a] (1979)(Radio Shack)(pdf).zip
  • This is the general users manual that comes with the Model I Expansion Interface. It contains system setup and cable connection information as well as technical details such as schematics, memory map, and I/O Port addresses.
• TRSDOS & Disk Basic Reference v2.3 (1979)(Tandy)(pdf).zip
  • This is for disk based Model I systems. The first section covers system setup (hooking up floppy disk drives, etc.). The other sections cover TRS-DOS v2.3 and Disk BASIC. If using a different DOS (like LDOS), you'll need manuals specific to that DOS. Even when using a different DOS, however, this manual is still important because it contains lots of basic information about system setup and how to use your disk system.
• Mini Disk Operators Manual (19xx)(Radio Shack)(pdf).zip
  • This is an older, but shorter version of the information contained in the TRSDOS & Disk BASIC Reference manual. It covers only the details about connecting floppy disk drives to an Expansion Interface and handling floppies. Scan quality is very poor.
• RS-232-C (1978)(Tandy)(pdf).zip
  • This manual covers the optional RS-232-C interface board that can be installed in an Expansion Interface.

Technical Reference and Service Manuals

• Radio Shack TRS-80 Micro Computer Technical Reference Handbook 2nd.zip
  • This is the main technical reference manual for the Model I computer (the keyboard). This is the second edition manual. It includes schematics, theory of operation, trouble shooting, etc. It does not cover the Expansion Interface. See the Expansion Interface Manual above, or the Service Manauls below for schematics, technical details, and trouble shooting for the Expansion Interface.
• Expansion Interface Service Manual (19xx)(Radio Shack)(pdf).zip
  • This is a Radio Shack service manual for the Expansion Interface. It covers the first generation Expansion Interface board including schematics, trouble shooting, etc. Unfortunately, this does not cover the buffer cable found on some first generation Expansion Interface systems.
• Expansion Interface Service Manual [Redesigned PCB] (19xx)(Radio Shack)(pdf).zip
  • This is a Radio Shack service manaul for the second generation Expansion Interface. The second gen Expansion Interface has the extra buffering integrated onto the board, replacing the need for the external buffer cable found on many first generation Expansion Interfaces systems.
• Sams ComputerFacts - Model I (1985)(Howard Sams)(pdf).zip
  • This is a Sams ComputerFacts book for servicing the TRS-80 Model I including the Expansion Interface and video display. This is not a Radio Shack manual. It is provided here because it has details on repair of the Model I video dispaly which is not covered in the other manuals above. It also covers the cassette modification board found in most TRS-80 Model I keyboards. This modification is not covered in the service manuals from Radio Shack.