TRS-80 Color Computer Controller 26-3022 (Controller ONLY)(25)

NOTE: This is for the controller only, no drives or cables

Controller

The 26-3022 Mini-Disk System was the first production release of a disk controller/drive for use with the original Color Computer.

The controller is based on the Western Digital WD1793. It features an analog data seperator circuit, infamous for its inherent unreliability and has multiple potentiometers which are used to calibrate various delay and timing features of the disk-side interface. It requires a +12 volt DC supply to operate, and is thus not compatible with a CoCo 2 or 3 unless a Multi-Pak Interface (or other source of +12V) is used or the CoCo or controller are "hacked", also contains the Disk BASIC ROM chip, and the necessary interface logic.

The 26-3022 controller was though to be the only one capable of being modified (though with considerable difficulty) to allow use with high-density 3.5" floppy drives. Early 26-3029 controllers had a Fujitsu MB8877A (5-volt only equivalent of the WD1793) and are also capable of HD drive operation. Mike Pepe has a page showing how he upgraded a 26-3029 controller: [1]

All subsequent controllers use the WD1773 controller chip, do not use the unreliable analog data separator, do not require +12V (so they will work with any CoCo model), and are capable of double-density operation only.