Retro Computer System

Tandy CoCo 2 and 3 Guide

The Tandy Color Computer 2 and Color Computer 3 are two of the best-known members of Radio Shack's 8-bit Color Computer family. Popular for BASIC programming, games, education, and hardware expansion, the CoCo platform still has an active hobbyist community today. This page brings together my CoCo 2 and CoCo 3 videos, restorations, upgrades, software, and related projects, with more in the full archive.

"Put the world of color computing into your home" - Radio Shack (a division of the Tandy Corporation)

Color Computer 2 and 3 Videos, Hardware, and Resources

Explore the Tandy Color Computer 2 and Color Computer 3 through restoration projects, memory and CPU upgrades, software, accessories, and hands-on videos from the Geek With Social Skills archive.

Videos and Projects

This section features Geek With Social Skills videos covering Color Computer 2 restoration, Color Computer 3 upgrades, hardware preservation, software, and related CoCo projects.

Color Computer 2

Color Computer 3 Upgrades

Software, Hardware, and Collecting

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System Overview

The Color Computer line was Radio Shack's Motorola 6809-based home computer platform. The Color Computer 2 refined the earlier design with a smaller case and revised hardware, while the Color Computer 3 introduced substantially expanded memory, improved graphics, additional video outputs, and a more capable memory-management architecture while retaining strong compatibility with earlier CoCo software and accessories.

  • Color Computer 2 introduced: 1983
  • Color Computer 3 introduced: 1986
  • Platform: 8-bit home computers sold through Radio Shack
  • Processor family: Motorola 6809E / 68B09E
  • Programming environment: Color BASIC and Extended Color BASIC
  • Storage: cassette, floppy disk, and ROM Program Pak cartridges
  • Expansion: cartridge expansion port with support for disk controllers, Multi-Pak hardware, and other peripherals
  • Common uses: programming, games, education, productivity, telecommunications, and hobbyist projects

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Color Computer 2 Specifications

The Color Computer 2 was an evolutionary refinement of the original TRS-80 Color Computer. Multiple revisions were produced, so memory, BASIC ROM configuration, keyboard style, and some internal hardware can vary between individual machines.

  • Processor: Motorola MC6809E, approximately 0.895 MHz
  • Memory: commonly 16 KB or 64 KB depending on model and configuration
  • Built-in language: Color BASIC, with Extended Color BASIC on equipped models
  • Graphics: Motorola MC6847 or later MC6847T1 Video Display Generator depending on model
  • Display: RF television output
  • Storage interfaces: cassette and optional floppy disk through expansion hardware
  • Cartridge support: ROM Program Pak cartridges through the side expansion slot
  • Controllers: two joystick interfaces
  • Serial connectivity: serial printer and communications support through the built-in serial interface

My CoCo 2 restoration project also involved troubleshooting the MC6809EP processor, SAM circuitry, RAM, socketed integrated circuits, and other components before returning the barn-find system to a working Extended Color BASIC startup screen.

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Color Computer 3 Specifications

The Color Computer 3 retained the 6809 architecture while significantly expanding the platform. Its redesigned graphics and memory system made higher-resolution displays and larger memory configurations practical while maintaining compatibility with much of the existing CoCo software library.

  • Processor: Motorola 68B09E / 6809E-family processor
  • Standard memory: 128 KB RAM
  • Factory-supported expansion: up to 512 KB RAM
  • Built-in language: Color BASIC and Extended Color BASIC environment
  • Graphics and memory control: GIME integrated graphics and memory-management hardware
  • Video outputs: RF, composite, and analog RGB
  • CPU operating speed: original CoCo-compatible speed with a higher-speed operating mode of 1.79 MHz
  • Expansion: cartridge port compatible with Program Paks, disk controllers, Multi-Pak hardware, and other CoCo peripherals
  • Keyboard: expanded keyboard with additional function and control keys

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Upgrades and Expansion

The Color Computer platform remains especially interesting because of the number of upgrades developed both during its commercial life and by the modern CoCo community. My own CoCo 3 has been used for several hardware projects that extend the machine well beyond its original configuration.

Memory Upgrades

CPU and Reliability Upgrades

These upgrades reflect one of the strengths of the CoCo community: original machines can remain recognizable and usable while benefiting from modern memory, protection, storage, and expansion hardware.

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Software and Storage

The Color Computer family supported software distributed on cassette, floppy disk, and ROM cartridges. Radio Shack sold Program Pak cartridges and disk systems, while third-party publishers and hobbyist developers built a large library of games, utilities, educational programs, productivity software, and operating-system tools.

Software Featured in My CoCo Projects

  • Dungeon of Daggorath
  • Galactic Attack
  • Arkanoid
  • Tetris
  • Sierra On-Line's King's Quest
  • Jumping Joey by Nickolas Marentes
  • Pipes by Nickolas Marentes
  • Rally SG by Nickolas Marentes

My SepTandy 2023 collection video also features a Color Computer Mini Disk Drive, joystick controllers, manuals, Program Pak cartridges, and both classic and modern CoCo software.

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History and Development

The Color Computer 2 arrived in 1983 as a smaller and more cost-effective refinement of Radio Shack's original Color Computer. It retained the Motorola 6809 architecture and broad software compatibility while appearing in multiple configurations with different memory capacities, keyboards, BASIC ROMs, and video hardware.

The Color Computer 3 followed in 1986 and represented a much larger technical step. Standard memory increased to 128 KB, expansion to 512 KB became practical, and the new graphics and memory architecture provided capabilities beyond the earlier MC6847-based machines. Composite and analog RGB outputs also made the CoCo 3 more flexible for higher-quality displays while retaining compatibility with much of the existing Color Computer software and hardware.

Although Radio Shack eventually moved away from the Color Computer line, the platform continued to attract programmers, hardware designers, collectors, and preservation enthusiasts. Modern upgrades, storage devices, homebrew software, and community events such as SepTandy continue extending the life of the CoCo decades later.

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