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Sharp Compet 30 (CS-30A or CS-30B) Desktop Calculator

Sharp Compet 30 (CS-30A)
Image Courtesy Takaharu Yoshida

It appears that there were two versions of the Compet 30 developed and marketed, the CS-30A, and the CS-30B. While visually very similar, the two versions of the machine were quite different. The CS-30A was implemented entirely using discrete transistor circuitry. The CS-30B utilized early small-scale integrated circuit devices in its sequencing logic. The CS-30A did not have the ability to represent negative numbers. For example, if one carried out a calculation that would normally result in an answer of -2, the calculator would display 99999999999998. This was corrected in the CS-30B, by inclusion of the ability to display negative numbers correctly. The CS-30B also added two indicators at the left end of the display that provided error (overflow) indication, and also notifed the user when the memory register contained non-zero content. The CS-30A did not have these indicators. Both the CS-30A and CS-30B used static Nixie drive circuitry (not multiplexed), identical keyboard and Nixie display assemblies, and appear to be visually identical other than the added indicators at the left end of the display in the CS-30B. The museum is interested in acquiring either version of the Compet 30.

Sharp Compet 30 Specifications

Manufacturer: Hayakawa Electric Co., Ltd. (Sharp)
Model Number: CS-30A/CS-30B (Compet 30)
Manufactured In: Japan
Date of Introduction: CS-30A: Late 1966
CS-30B: Spring, 1967
Display Technology: Nixie Tube, 14 Digits
Logic Technology: CS-30A: Discrete Diode-Transistor Logic
CS-30B: Discrete Diode-Transistor with IC-based Control Sequence circuitry
650 Transistors, 1600 Diodes (CS-30A)
Digits of Capacity: 14
Decimal Modes: Fixed via keyboard pushbuttons
Math Functions: Four Function
Memories: One memory register
Performance: Addition/Subtraction: 15ms; Multiplication/Division: 150ms
Size: 17 1/4" wide, 18 3/4" deep, 8 1/2" high
Weight: 29 pounds
Power Consumption: 25 Watts

Copyright ©1997-2019, Rick Bensene.