The Scelbi-8B microcomputer was one of the earliest commercially available personal computers, released in 1975 as an improved version of the Scelbi-8H. Based on the Intel 8008 microprocessor, it represented a pioneering effort to bring computing to hobbyists and small businesses during the dawn of the microcomputer era.
The Scelbi (pronounced "sell-bee") computers were developed by Nat Wadsworth and Robert Findley, who founded Scelbi Computer Consulting Inc. in Milford, Connecticut, in 1973. The company name was an acronym for SCientific ELectronic BIological, reflecting their vision of versatile applications in science and business. Wadsworth, an electronics engineer, became enthralled with the Intel 8008 after attending a 1972 seminar and saw its potential for building affordable computers. He partnered with Findley to design and market the systems.
The original Scelbi-8H ("H" for Hobby) was first advertised in March 1974 in amateur radio magazines, making it arguably the first microprocessor-based computer kit sold commercially in the United States. It was available as a kit or fully assembled. The 8H did not sell in large numbers, leading to its discontinuation by late 1974.
In 1975, Scelbi introduced the improved Scelbi-8B ("B" for Business), targeted at small business and professional users. It featured expanded memory capabilities and better support for peripherals. Approximately 200 Scelbi computers were produced in total (half 8H, half 8B), with many sold as kits for around $580 assembled or less in kit form. The company also offered chassis, power supplies, and interface boards separately.
The Scelbi-8B used the Intel 8008 8-bit microprocessor, running at a clock speed of approximately **0.5 MHz** (500 kHz). Key features included:
Programs were entered in machine code via front-panel switches, with output shown on LEDs. Later software like SCELBAL (a BASIC interpreter) made it more user-friendly when paired with peripherals.
Scelbi was notable for its early software efforts. Wadsworth authored books like Machine Language Programming for the 8008 and Similar Microcomputers (1975), which included floating-point routines. In 1976, they released SCELBAL, a BASIC language variant developed with Mark Arnold, allowing higher-level programming. These publications became highly successful, eventually shifting the company's focus from hardware to books and software.
Though overshadowed by the more powerful Intel 8080-based Altair 8800 (introduced in 1975), the Scelbi-8B contributed to the early microcomputer movement. It predated many famous systems and demonstrated that complete computers could be built affordably by individuals. Sales were limited due to the 8008's slower performance and the rapid shift to the 8080.
Scelbi ceased hardware production by 1976, but the publishing arm thrived until sold in 1982. Surviving Scelbi machines are extremely rare today, prized by collectors and featured in museums like the Computer History Museum. The Scelbi-8B embodies the innovative spirit of the 1970s hobbyist era that sparked the personal computer revolution.