This system was purchased in November 2013 for $200 (plus about $35 shipping). The reason for this purchase, was the replaced CPU board. Instead of the standard Heath CPU board, this system has the TMSI H-1000, which has both the 8-bit Z-80 and 16-bit 8086 CPUsto run both 8-bit and 16-bit software.




This system was also EXTREMELY well packed. They used double boxing, to insure the system did not directly feel shipping impacts. The H89 itself was wrapped in large bubble wrap. Even though this system has the original, poorly constructed CRT mounts, none of them broke during shipping.

Initial Testing

I've only spent about 20 minutes with this system. The system only beeps once, and it doesn't seem to respond to any keyboard presses (either on-line or off-line). The voltages seemed fine. Nothing appears on the screen, I've tried turning the brightness knob (this system did not have the external knob, but it was only on the video card under the CRT), and still did not see anything, not even a blinking cursor.

Unique Components

This system has the TMSI H-1000 CPU board and a bunch of push buttons. I'm not sure what they do.



Dirty keyboard and sticky keys. It will need to be taken apart and cleaned thoroughly.





The TMSI H-1000.


The soft-sectored Controller - Z-89-37.



5 right slots on the H-1000



The lower right side of the H-1000 where the CPUs are (I need to take a better picture).




Strange board that was loose inside the H-89.



Back side of the strange board.




Keyboard pull out, showing the standard ribbon cable and a bunch of other wires.



Wires all coming into the board.




Closer look.



Another board behind the keyboard.




A broader look at it.



Same board with yellow cushion removed.




Back side of the same board.



Cabling on the H-1000.




Closer look at the cabling.



Some cabling and attached to the terminal board.




Another look at the boards behind the keyboard.



Some other cables behind the keyboard.




Appears to be a variable resistor that may control the frequency of the speaker - which it is attached.



Showing the H-1000 and TMSI print on the board.




Clearer shot of the logo.

Next Steps

Need to determine why there is no video, and then verify operation.


Last Modified: Wednesday, 16-May-2018 22:48:18 PDT

Contact Details

Mark Garlanger

Email: mark [at] garlanger [dot] com

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Website: www.garlanger.com


This site is dedicated to preserving the history of the original Heathkit computers. They were initially release in 1977 and included the 8-bit H-8 and 16-bit H-11 systems. The H89 was released in 1979.