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Litronix Checkmate

Date of introduction:	1973	Display technology:	LED-modules
New price:		Display size:	8
Size:	5.4" x 3.1" x 1.4" 138 x 78 x 36 mm³
Weight:	5.7 ounces, 163 grams	Serial No:	20917
Batteries:	5*AA cells	Date of manufacture:	mth 05 year 1973
AC-Adapter:		Origin of manufacture:	USA
Precision:	12	Integrated circuits:	LIT-019
Memories:
Program steps:		Courtesy of:	Joerg Woerner

Litronix, Inc., (Cupertino, CA) was an early light-emitting diode (LED) company that became a leading supplier of displays for handheld calculators and digital watches (e.g. the Hamilton Pulsar line).

This Checkmate was the first portable electronic calculator developed and manufactured by Litronix. It is one of the rare designs using the original Klixon™ keypad without the TMS0100 MOS/LSI calculator-on-a-chip. The printed circuit board (PCB) of the Checkmate is centered around a LIT-019 calculator circuit, discrete display drivers (the two white ceramic housings are current limiting resistors manufactured by Beckman), and three Litronix display modules with 3 digits each.

Maybe you noticed already the unusual lettering of the decimal switch above the [-=] key. Instead the usual 0-2 selection it gives a 2-4 selection. The Checkmate is one of the few portable calculators without floating point operation.
The label on the back gives an example for calculations with small numbers with the decimal switch set to "4":

.17 : 9 = .0188

The Checkmate was later replaced with the Checkmate 1002 assembled in Malaysia. Don't miss a second version of the Checkmate sporting a different keyboard and only three batteries.

If you have additions to the above article please email: joerg@datamath.org.