D-G Electronic Developments Super 89  
Written by Accutron on 2017-03-17  

Devices included in this entry:

D-G Electronic Developments Super 89 CPU card (pictured in thumbnail)
Heath/Zenith Z-89-37 Double Density Disk Controller (pictured in thumbnail)
Heath/Zenith Z-89-67 Interface Board (pictured in thumbnail)


The D-G Electronic Developments Super 89 is an aftermarket replacement CPU upgrade for the Heath/Zenith H-88/H-89/Z-89/Z-90 series of Z80-based all-in-one personal computers. The Super 89 substantially outperforms the standard H-89 CPU, as it operates at double the original 2MHz clock rate, has a built-in real-time clock, optional AM9511A arithmetic processor and up to 256K of bank-selectable RAM. The example in our collection has two official Heath/Zenith interface cards installed: the Z-89-37 Double Density Disk Controller, and Z-89-67 Interface Board, designed for use with the Z-67 Winchester drive. The Z-89-37 is noteworthy as being the differentiating component between the H-89/Z-89 and the Z-90. While the H-89/Z-89 uses an older hard-sectored floppy disk controller, the Z-90 is equipped with the Z-89-37, which controls the H-37/Z-37 soft-sectored DSDD floppy drive.

D-G also manufactured the Heartbeat, a Heath/Zenith compatible system that was little more than a Super 89 in a box. Unlike the Heath/Zenith machines, the Heartbeat requires a separate terminal to provide the user interface.

Special thanks to Victor Rizzardi for donating this hardware.

D-G Heartbeat / Super 89 Operation Manual (PDF)


D-G Electronic Developments Super 89 CPU card with two Heath/Zenith interface cards installed.


Heath/Zenith interfaces: the Z-89-37 Double Density Disk Controller and Z-89-67 Interface Board.

This article is part of the [Logic & Memory Circuits] exhibit.

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