The Oojamaflip 2021 – Kit Version


What is the Oojamaflip 2021?

The Oojamaflip is a cartridge port expansion device. It extends the existing cartridge port outwards and provides an additional cartridge port internally – flipped over by 180 degrees. The 2021 model now includes pull-up resistors (see 6809 Pull-up Resistors) for enhanced compatibility between complex peripherals.

Oojamaflip 2021 Build Instructions v1

Not electrically suitable for Tandy Coco 3 if pull-up resistors are fitted, as these are incorporated in the Coco 3 as standard.

Looking for the built version? You’ll find it here.

In stock


Please note that this product is not electrically suitable for use in a Tandy Coco 3 computer if the pull-up resistors are fitted, as the Coco 3 design incorporates these as standard. This version of the board is now electrically (if not physically) compatible with the Coco 1 computer.

The Oojamaflip 2021 is a enhanced version of a device manufactured in the late 1980s for the Dragon 32 & 64 computer by Richard Sutcliffe of Sutcliffe Electronics. His original boards were very ingenious and well made devices which have stood the test of time.

The Oojamaflip 2021 permits the connection of some of the newer peripherals alongside one of the virtual disk solutions, like DragonMMC, DragonDrive or CocoSDC. The main use so far has been for connecting the prototype V9958-based Dragon MSX 2+ board to a Dragon 64 at the same time as the DragonMMC or CocoSDC. The main differences between the Oojamaflip 2020 and the Oojamaflip 2021 are:

  • Cartridge port pins 1 & 2 are no longer joined. This ensures electrical compatibility with the Coco 1.
  • Provision is made for pull-up resistors (see 6809 Pull-up Resistors) on RD/WR and all address lines. This provides compatibility between the CocoSDC and the Dragon MSX 2+ board.
    • If you have an Oojamaflip 2020, and need this enhancement, then you can also try our CPU adapter board, which implements the same fix.

It may not support everything (especially if devices have conflicting address locations) – but it does certainly allow more flexibility on the cartridge port.

Please bear the following in mind before ordering:

  • whilst these work, and are of sound quality, they are still considered experimental.
  • you will receive the components to make the board only – any internal fixings to make secure the board or peripherals are your responsibility.
  • Instructions can be downloaded here. In order to reduce package size, none are included in the kit.
  • the board will be supplied with a 2-pin header and a jumper to connect the +5v line. If you wish to add a switch, it is left to you to work out your own solution as regards connectivity etc.
  • The product is not guaranteed to fit inside any Tandy Coco machine, as it has been designed for use inside Dragon computers. It should be functionally compatible with Coco 1 & 2, if not physically compatible. Only electrically compatible with the Coco 3 if the pull-up resistors are NOT fitted.


Additional information

Weight 0.055 kg

New: Other

Mostly new components and PCB. Some old components – fully tested – but due to age, leaded solder will be present.