Exactra 23 by Texas Instruments 

Date of introduction:  October 1974 Display technology:  LED-stick w/o lens
New price:   Display size:  8
Size:  5.1" x 2.9" x 1.3"
 130 x 74 x 34 mm3
Weight:  5.1 ounces, 144 grams Serial No:  2300021274
Batteries:  3*AA  Date of manufacture:  wk 48 yr 1974
AC-Adapter:  AC9160 Origin of manufacture:  USA
Precision:  8 Integrated circuits:  TMS0803
Program steps:   Courtesy of:  Joerg Woerner
    Download manual:   (US: 1.9M Bytes)

The Exactra 23 could be called the fully loaded model in the cheap Exactra line. It sports an 8-digit display, a %-key and a connector for an external power supply. This position in the Exactra line is demonstrated to the customer with a valuable golden line around the keyboard.

Dismantling the Exactra 23 revealed two small surprises. First of all the LED-display found in this particular calculator was manufactured by Bowmar. We know the Opto-stick display with he small numbers already from the TI-2500B.

Second surprise is the TMS0803 single-chip calculator circuit known from the Exactra 21 and Exactra 22. But these siblings miss the %-key - once again the "power of marketing". Nevertheless the Exactra 23 uses a different layout of the printed circuit board (PCB). At first glance the schematics of the calculators seem to be identical with a tiny display driver and two additional transistors plus a power-converter. 

A similar calculator was sold as Citation M4993 by the distribution company Western Auto and by Montgomery Ward with the TXI-8661A.


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