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Addo-X 9958 Desktop Calculator

Image Courtesy Andreas Zinn

Early bipolar (TTL) IC and transistor hybrid calculator. Marketed by Swedish company Addo-X (A.B. Addo) under OEM agreement with Sharp. A few early small-scale integrated circuits are used, along with a vast majority of discrete transistor and diode-resistor logic circuitry. 16-digit capacity, two independent accumulator-type memory registers. Fixed decimal with knob-selectable settings of 0, 2, 3, 4, or 8 digits behind the decimal. Provides square root function by pressing "" key followed by "=" key. Virtually identical other than color scheme and subtle cabinetry variations to the Burroughs C-3350 calculator, also OEM'd by Burroughs from Sharp.

Visit the Old Calculator Web Museum exhibit on the Burroughs C-3350 for more information about a similar design calculator marketed by Burroughs.
Addo-X 9958 Specifications

Manufacturer: Addo-X
Model Number: 9958
Manufactured In: Japan (by Sharp for Addo-X)
Display Technology: Nixie Tube, 16 Digits
Logic Technology: Mix of early bipolar small-scale IC's and discrete diode/transistor logic
Small magnetic core memory array for working register storage
Digits of Capacity: 16
Decimal Modes: Fixed at rotary switch-selectable locations, automatic round-off
Math Functions: Four Function plus two-key Square Root
Memories: Two accumulator-style memory registers
Size: Approx. 12 1/4" wide, 16" deep, 4 1/2" high
Weight: Approx. 14.5 pounds
Power consumption: 40 Watts

Copyright ©1997-2021, Rick Bensene.