Heathkit IC-2108

This Heathkit IC-2108 was the third desktop calculator in a line started with the IC-2008 and followed by the IC-2008A before the IC-2100 introduced in December 1974 marked the end of Heath' kit calculators. The new design of the IC-2108 gives a very sleek profile that fits easily into a brief case.

Dismantling the featured Heathkit IC-2108 sold in December 1973 to an American hobbyist and assembled in picture-perfect quality, reveals a design centered around a Texas Instruments TMS0119 single-chip calculator circuit on a conveniently large printed circuit board (PCB) surrounded by the power supply and many discrete transistors and other components.

The TMS0119 is a member of the TMS0100 Product Family introduced already in September with the TMS1802, later renamed to TMS0102. Other applications of the TMS0119 are different versions of the TI-2500 Datamath calculator manufactured between September 1972 and mid of 1974 including the TI-2510.

The Main-PCB is connected in typical Heathkit tradition with individual wires to the Keyboard-PCB and a third PCB with discrete high-voltage drivers and three 3-digit Sperry SP-753 planar neon gas discharge "Panaplex II" display modules.

The Keyboard-PCB is using eighteen individual short-stroke push-button switches for the numbers and functions and three rocker switches for power, constant and a configurable (during assembly of the calculator with a wire) decimal point.

The IC-2108 calculator was available till May 1974, the priced dropped within a few months down to $69.95.

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

© Joerg Woerner, January 11, 2002. No reprints without written permission.