The Jim Austin Computer Collection

Heathkit H8 Digital Computer 

This is an early digital computer kit made by Heathkit. This came from Cardiff, in the UK in 2009. A bit about it from the suppler.

The Heath Company became incredibly well known in the 1960s and 1970s for their array of build-it-yourself radio and amplifier kits. The company leaped into the electronics kit market by purchasing surplus electronic components after WWII. Their first product was a $50 oscilloscope, introduced in 1947. The company flourished during the early transistor era, because it was possible for hobbyists to build kits at a substantial saving compared to fully manufactured devices. The emergence of microelectronics and offshore manufacturing began to erode the advantages of kit building in the 1970s, so they looked to the next frontier: microcomputers.

The Heathkit H8 computer was introduced in 1977, at a time when the idea of a kit-built computer seemed perfectly reasonable. The machine sold well and attracted the attention of Zenith, who offered fully assembled versions of Heath machines starting in 1979. The machine featured an Intel 8080 processor running at 2MHz. The front panel offered a 4K RAM, a 16 button keypad and a cryptic 9 digit LED display. A basic kit could be had for as little as $375, but most users added external serial terminals, up to 64K of memory, and floppy disk drives. there were up to ten expansion slots inside the machine, allowing you to add 3 parallel ports ($150), a cassette interface ($110), and even a fancy $675 floppy drive which required upgrading to 16K of RAM ($375). he Heath Company became incredibly well known in the 1960s and 1970s for their array of build-it-yourself radio and amplifier kits. The company leaped into the electronics kit market by purchasing surplus electronic components after WWII. Their first product was a $50 oscilloscope, introduced in 1947. The company flourished during the early transistor era, because it was possible for hobbyists to build kits at a substantial saving compared to fully manufactured devices.

Pictures of the machine:

Behind the front panel

Inside the machine

The rear of the machine.

This H8 machine seems to have come from a shop in Canada, as the manuals are stamped with 'shop copy do not sell'. Unfortunately it does not have any software with it or a disk drive, but all the manuals and an interesting music card in the system.

Model HN-8-66

• Main processor card April 1979.
• 8K static Ram.
• Controller board (for disks).
• H8-4 Multi-port serial i/o card.
• HA8-2 Music synthesizer board.
• H8-5 Serial i/o.

Folder 1:

• Video Terminal Model H9 assembly 1977
• Video Terminal Model H9 operation 1977

Folder 2:

• Digital Computer Model H8 Assembly manual 1977
• Digital Computer Model H8 Operation manual 1977
• 4K static memory Model H8-1 assembly 1977
• Multi-port serial i/o card Model H8-4 assembly manual 1978
• Multi-port serial i/o card Model H8-4 operation manual 1979
• Schematic of the H8 front panel, motherboard and chassis
• Illustration booklet of front panel
• Illustration booklet of Chassis
• Illustration booklet of parts.
• Serial i/o and cassette interface card Model H8-5 assembly manual 1977
• Schematic of Serial i/o and cassette interface card H8-5
• HA8-2 Board and music software documentation. New or lines general data services inc 1980

Folder 3:

• Microsoft Basic for the Heath 8-Bit Digital Computer System Model H8-21 1979
• Software reference manual.
• Chapter 0 HDOS system configuration for the H8-17
• chapter 1 Operating instructions
• chapter 2 console debugger debug
• chapter 3 heath text editor
• chapter 4 heath assembly language ASM
• chapter 5 extended benton harbour BASIC