Heathkit briefly sold an
analog computer in 1957. Before entering the burgeoning home computer market, Heathkit marketed and sold microprocessor-based systems aimed at learning about this technology. The ET-3400, for example, was released in 1976 and was based on the
Motorola 6800 microprocessor. This system included 256 bytes of RAM, a 1k monitor in ROM, and a keypad for easy entry and modification of programs. Despite being a small trainer kit, it was powerful and flexible enough to be used in rudimentary control systems. In 1977, the company announced two digital computer kits:
Heathkit H11—based on the 16-bit
DEC LSI-11—and lower-end
Heathkit H8. With $90 million in sales in 1976, the company hoped that computers would soon provide more than 20% of revenue. The H8 was very successful, as were the
H19 and
H29 terminals, and the
H89 "All in One" computer. The H8 and H89 ran the Heathkit custom operating system
HDOS as well as the popular
CP/M operating system. The H89 contains two Zilog
Z80 8-bit processors, one for the computer and one for the built-in H-19 terminal. The H11 was less successful, probably because it was substantially more expensive than the 8-bit computer line. By fiscal year 1980 computers were 40% of Heathkit revenue. Seeing the potential in personal computers,
Zenith Radio Company bought Heath Company from Schlumberger in 1979 for $63 million, renaming the computer division
Zenith Data Systems (ZDS). Zenith purchased Heath for the flexible assembly line infrastructure at the nearby St. Joseph facility as well as the R&D assets.
Ready-to-assemble furniture appeared in Heathkit catalogs, manufactured by Zenith TV-cabinet factories with excess capacity. Heath/Zenith was in the vanguard of companies to start selling personal computers to small businesses. The WH-89 assembled version of the H-89 kit was re-branded as the
Zenith Z-89/
Z-90, an assembled all in one system with a monitor and a
floppy disk drive. They had agreements with
Peachtree Software to sell a customized "turn-key" version of their
accounting, CPA, and
real estate management software. Shortly after the release of the Z-90, they released a 10MB
hard disk unit and double-density external floppy disk drives. While the H11 was popular with hard-core hobbyists, Heath engineers realized that DEC's low-end PDP-11 microprocessors would not be able to get Heath up the road to more powerful systems at an affordable price. Heath/Zenith then designed a dual Intel
8085/
8088-based system dubbed the
H100 (or
Z-100, in assembled form, sold by ZDS). The machine featured advanced for the day bit mapped video that allowed up to 640 x 225 pixels of 8 color graphics. The H100 was interesting in that it could run either the
CP/M operating system, or their OEM version of
MS-DOS named
Z-DOS, which were the two leading business PC operating systems at the time. Although the machine had to be rebooted to change modes, the competing
operating systems could read each other's disks. After hinting at a robot at the 1982
West Coast Computer Faire, that year Heath introduced the
Hero-1 robot kit to teach principles of industrial robotics. The robot included a
Motorola 6808 processor, ultrasonic sensor, and optionally a manipulator arm; the complete robot could be purchased assembled for $2495 or a basic kit without the arm purchased for $999. This was the first in a popular series of Heathkit robot kits sold to educational and hobbyist users. == Kit era comes to a close ==