Click Here to visit our Sponsor
The History of Computing The Magazine Have Fun there ! Buy goodies to support us
  Mistake ? You have mr info ? Click here !Add Info     Search     Click here use the advanced search engine
Browse console museumBrowse pong museum


ZX Spectrum T-shirts!

see details
ZX81 T-shirts!

see details
Ready prompt T-shirts!

see details
Atari joystick T-shirts!

see details
Spiral program T-shirts!

see details
Arcade cherry T-shirts!

see details
Battle Zone T-shirts!

see details
Vectrex ship T-shirts!

see details
Moon Lander T-shirts!

see details
Competition Pro Joystick T-shirts!

see details
Elite spaceship t-shirt T-shirts!

see details
Atari ST bombs T-shirts!

see details
C64 maze generator T-shirts!

see details
Pak Pak Monster T-shirts!

see details
BASIC code T-shirts!

see details
Breakout T-shirts!

see details
Pixel adventure T-shirts!

see details
Vector ship T-shirts!

see details

T > TANDY RADIO SHACK  > Color Computer 3   

Tandy Radio Shack
Color Computer 3

The "TANDY Color Computer 3" followed the Color Computer 2.

The CoCo3 came with 128K RAM, an analog RGB video port, enhanced 640x192 graphics capability, a 64-color palette and much more. (All ports contained on the CoCo 1 and 2 models were also available on the CoCo3, e.g. RS-232 serial, cassette, right and left joystick and a 40-pin expansion slot.)

The built-in Language, named Disk Extended Color Basic 2.1, was a Microsoft BASIC with enhancements by Microware. It was similar to that of the CoCo2, but Microware added the commands/functions to take advantage of the higher resolution graphics and text.

The CoCo3 was upgradeable to 512 KB RAM. (After-market RAM upgrades have gone as high as 8MB, with rumors that 16MB and 32MB RAM upgrades may also be possible). A Multi-Pak (a 4-port bus expander) plugged into the Expansion Slot allowed use of controllers for floppy disk drives, hard drives (MFM, RLL, SCSI and now even IDE), multi-port true RS-232 devices, MIDI units and much much more.

As its microprocessor was still an 8 bit (strange choice when Atari and Commodore were using a 68000), it couldn't access simultaneously to the 128k (or 512k), and thus used several RAM banks which could be switched (as the Thomson TO8, or MSX 2 computers).
Unlike the CoCo and CoCo II the 3 had an interrupt controller. This did away with a lot of the timing loops used in its predecessors, and actually took some of the fun out of programming in Machine Language.

Tandy made several prototypes of a Color Computer model IV but it was never released.


Contributors: D. Francis

Please consider donating your old computer / videogame system to or one of our partners from anywhere in the world (Europe, America, Asia, etc.).


Website link is for Tandy CCR (Cassette Recorder) information. Also, does anyone know if the CoCo3 video output can all be used at the same time? (for mirror display output, such as the RF coax output + RCA composite output, and maybe the RGB as well? )

Thursday 20th January 2022
Steve (USA)

Disk Extended Color Basic wasn''t available on any of the CoCo line without the addition of the Floppy controller and the included internal ROM that plugged into the 40-pin expansion slot or the Multi-Pack Interface (or equivalant.) Otherwise just Extended Color Basic was available for use.

Tuesday 7th April 2020
William (USA)

Michael Devenney, I am definitely interested. please E-mail me at

Monday 19th August 2019
Corey Lynch (United States)


NAME  Color Computer 3
MANUFACTURER  Tandy Radio Shack
TYPE  Home Computer
YEAR  1986
BUILT IN LANGUAGE  Disk Extended Color Basic 2.1 (Microsoft BASIC, with enhancements by Microware)
KEYBOARD  Full-stroke keyboard
CPU  Motorola 68b09e (uses an external clock generator)
SPEED  1.79 MHz (0.89mhz under RS-DOS for compatability with FD expansion unit)
RAM  128 KB (up to 512 KB. There were 1MB and 2MB upgrade boards as well)
ROM  32 KB
TEXT MODES  32x16, 40x25, 80x25
GRAPHIC MODES  Several graphic modes, the most interesting were: 320x200 (16 col.), 640x200 (4 col.), 640x400 (4 col. if 512 KB RAM)
SOUND  See comment below
SIZE / WEIGHT  Unknown
I/O PORTS  Tape, Composite Video, analog RGB connector for use with Tandy CM-8 monitor, 2 joystick ports, cartridge slot, RS232
OS  with optional disk drive : RS-DOS, OS-9 Level 2 was also popular
PRICE  $219.95 (USA, 1986)

Please buy a t-shirt to support us !
Ready prompt
ZX Spectrum
Arcade cherry
Spiral program
Atari joystick
Battle Zone
Vectrex ship
C64 maze generator
Moon Lander
Competition Pro Joystick
Atari ST bombs
Elite spaceship t-shirt
Commodore 64 prompt
Pak Pak Monster
Pixel Deer
BASIC code
Shooting gallery
3D Cubes
Pixel adventure
Vector ship

Related Ebay auctions in real time - click to buy yours

see more Tandy Radio Shack  Color Computer 3 Ebay auctions !

Click here to go to the top of the page   
Contact us | members | about | donate old-systems | FAQ
OLD-COMPUTERS.COM is hosted by - NYI (New York Internet) -