Date of introduction:  September 30, 1981 Display technology:  LCD
New price:  $24.95 (SRP Oct. 1985) Display size:  8
Size:  3.6" x 2.3" x 0.3"
 91 x 57 x 8 mm3
Weight:  1.3 ounces, 38 grams Serial No:  9592597
Batteries:  2*LR43 Date of manufacture:  August 1981
AC-Adapter:   Origin of manufacture:  Japan
Precision:  8 Integrated circuits:  NEC uPD1032G
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Does this Radio Shack EC-303 CHRONOMATH LCD calculator look familiar to you? Please compare it with the TI-1788 or KMC 2000, Privileg LC 6000, Systema LC1400 and probably many more offspring.

The Radio Shack EC-303 CHRONOMATH LCD calculator introduced in 1981 combines in a very compact package both a calculator with 3-Key Memory and a clock with alarm-time. We know similar, but larger products including a stopwatch since 1978 with the Canon LC Quartz, Toshiba LC-833WA, and Texas Instruments TI-1790.

Dismantling this Radio Shack EC-303 calculator manufactured in August 1981 by a non-disclosed Original Equipment Manufacturer (OEM) reveals a very clean design centered around a NEC uPD1032G single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) and powered by two small LR43 batteries. Learn how to decipher the 8A1 date code located inside the pictured calculator.

Inspecting the PCB of this Radio Shack EC-303 calculator brought our attention to a small mark reading CC-31 B, we noticed similar marks already with the TI-1788, TI-1788 II and TI-1788 III, the latter manufactured probably by Cal-Comp Electronics and started compiling a list of the PCB-Marks on calculators manufactured by OEMs for Texas Instruments.

We know the CC-11 mark with the Radio Shack EC-260 CHRONOMATH LCD a similar product introduced in 1979 and obviously manufactured by Cal-Comp Electronics in Taiwan.

If you have additions to the above article please email:

Joerg Woerner, April 19, 2020. No reprints without written permission.