Version 1, with "Klixon" keypad.
Version 2, with keypad from Wild Rover Corp.
Distinctive features: One of the first models of calculator made by Litronix, like Bowmar, a manufacturer of LED (Light-Emitting Diode) displays which moved into making the complete calculator.
Display is 8 digits, red LED, with fixed decimal point, switchable between 2 and 4 places of decimals.
Main integrated circuit is a LIT-019 (manufacturer unknown), here date coded 1973.
Checkmate version 1 has the high-quality Texas Instruments "Klixon" keypad, whereas version 2 has a somewhat cheaper keypad from Wild Rover Corp..
78 x 137 x 37 mm (3.1" x 5.4" x 1.5").
Litronix Inc., Cupertino, California, U.S.A.
The electronics of the version 1 and the version 2 models is identical. Since the version 2 model does not have the Litronix name on it and has a cheaper keypad, Ball & Flamme suggest that it may have been made by Litronix for another company to market.
Note that on the version 1 calculator displayed someone has engraved a security number "H58359" below the display and near the decimal position selector switch - calculators were expensive items at the time!
With the casing removed, showing the identical circuit boards of a type 1 version (on the left) and a type 2 version (on the right). The white and gold calculator integrated circuit, marked with the code
LIT-019, is prominent.
The LED display is at the top, with a row of individual transistors below.
Litronix was a manufacturer of LED displays which diversified into the manufacture of electronic hand-held calculators in the early 1970s.
It was a major supplier in the calculator market and produced a range of well specified and stylish models, with later ones being assembled in Malaysia. Like Bowmar it was badly hit by the plunging price of calculators in the mid-1970s and left the calculator market. It was bought by Siemens A.G. of Germany.
© Text & photographs copyright Nigel Tout 2000-2015 except where noted otherwise.