Texas Instruments CONCEPT II (Version 1) distributed by Zayre Corp.

Date of introduction:  March 1976 Display technology:  LED-stick
New price:  SRP $17.77 Display size:  8
Size:  5.5" x 2.8" x 1.4"
 138 x 70 x 35 mm3
Weight:  3.9 ounces, 110 grams Serial No:  1032920
Batteries:  9V  Date of manufacture:  wk 08 year 1976
AC-Adapter:  AC9180 Origin of manufacture:  USA (LTA)
Precision:  8 Integrated circuits:  TMS0972
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner
    Download manual:   (US: 1.1M Bytes)

Concept-II_Back.jpg (266810 Byte)Zayre Corporation was founded in 1956 by Stanley and Sumner Feldberg in Hyannis, Massachusetts as a discount department store chain. Zayre launched already in August 1975 the CONCEPT series of portable electronic calculators with the introduction of their first CONCEPT 24.

Concept-I_CMP1.jpg (88458 Byte)The Zayre CONCEPT Calculator Series culminated in March 1976 with the introduction of the Texas Instruments CONCEPT I, CONCEPT II, and CONCEPT III calculators based on the TI-1200, TI-1250, resp. SR-16 II but disappeared already in August 1979 with the clearance sales of the CONCEPT COMPACT calculators.

You have to look twice to catch the differences between this rare CONCEPT II and the TI-1250 calculator. The only differences between the calculator is the color scheme of the faceplate.

Dismantling the featured CONCEPT II calculator with Date code 0876 LTA and manufactured in February 1976 in Lubbock, Texas reveals a very efficient and cost-optimized design with a single-sided printed circuit board (PCB) centered around a TMS0952 single-chip calculator circuit based on the TMS1000, the World's first Microcomputer.

The TMS0952 used with the original TI-1200/TI-1250 was soon replaced with the TMS0972, a pin-compatible design dropping the additional resistors and capacitor and further reducing the manufacturing costs of the calculators.

Learn more about the evolution of the TI-1250 between June 1975 and its discontinuation in 1977.

Learn more about the different Product Labels used with the TI-1250 - here at the Datamath Calculator Museum we classify the featured CONCEPT II as Hardware Version 2, PCB Type 2 Cost Reduction and Product Label Style 3, Concept II.

The CONCEPT II calculator was introduced in March 1976 and discontinued already in January 1977 with the blow-out sales of the CONCEPT I, CONCEPT II, CONCEPT 10, and the 2nd and 3rd design of the CONCEPT 24 calculators.

Fellow collectors - if you own a Zayre CONCEPT calculator,  please report us the serial number and date code from the back of the calculator for our Database.

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If you have additions to the above article please email:

Joerg Woerner, December 5, 2001. No reprints without written permission.