Heathkit IC-2009

Heath Company of Benton Harbor in Michigan, United States, best known for their high-quality electronic kits branded Heathkit, announced already in March 1972 with the IC-2008 their first Electronic Desktop calculator and followed in December with this IC-2009 Portable calculator. At first glance the IC-2009 could be mistaken for a rebadged Bowmar 901B like the Commodore C110 or Craig 4501, but putting them side-by-side proofs different.

Dismantling the featured Heathkit IC-2009 sold in June 1973 to an American hobbyist and assembled in picture-perfect quality, reveals a design centered around a Texas Instruments TMS0103 single-chip calculator circuit on a compact printed circuit board (PCB) surrounded by integrated display drivers, a Klixon™ keyboard assembly, a small PCB with the LED display, many discrete transistors and other component and powered by 6 rechargeable NiCd batteries.

The TMS0103 chip is a modification of the TMS0102, the first member of the fast growing TMS0100 Product Family after the introduction of the TMS1802 on September 17, 1971. Main difference for the user of the TMS0103 was the introduction of an "Entry Overflow" notification missing with the TMS0102. When Texas Instruments introduced the TMS1802, their offering did not only include the single-chip calculator circuit but complete component kits including schematic diagrams for a quick design of an electronic calculator, too:

While many early electronic calculators make use of this component kit, opted Heathkit for different LED displays and the featured IC-2009 calculator sold in June 1973 uses a Bowmar Optostic R7H-122-9.

The priced of the IC-2009 dropped down to $89.95 before the calculator was replaced in October 1973 with the IC-2006. The Heathkit IC-2006 uses a much smaller housing with a complete different, TI-less design. 

If you have additions to the above article please email: joerg@datamath.org.

© Joerg Woerner, September 28, 2003. No reprints without written permission.