DATAMATH CALCULATOR MUSEUM
Montgomery Ward P800 aka TXI-8642A
|Date of introduction:||Display technology:||LED-modules + lens|
|New price:||Display size:||8|
|Size:|| 5.8" x
3.4" x 1.45"
147 x 87 x 37 mm3
|Weight:||10.1 ounces, 287 grams||Serial No:||37B-26340|
|Batteries:||4*AA NiCd||Date of manufacture:||year 1973|
|AC-Adapter:||Origin of manufacture:||USA|
|Precision:||8||Integrated circuits:||TMS0109 or TMS0103, 2*SN75491, 2*SN75492|
|Program steps:||Courtesy of:||Joerg Woerner|
This boxy calculator does not look like a Texas Instruments product. To identify it, you have to know more about the coding on the product labels used by Montgomery Ward:
Models starting with
• TXI were
manufactured by Texas Instruments
• DAN were imported by APF Electronics, Inc.
• DNS were manufactured by National Semiconductor (later Novus)
• EKJ were imported by Kings Point Corporation
• GLE were manufactured by Lloyd's Electronics, Inc.
dig deeper into the calculator you'll notice that the
P800 is very similar to the TI-2500 Datamath.
The circuit diagrams look identical, the single-chip calculator circuit is either the TMS0109
borrowed from the TI-3000 or the
TMS0103 found in the Bowmar
901B. The other components located on the printed circuit board (PCB) of the
featured calculator manufactured in 1973 are well known from the reference
design of the TMS0100, namely two
SN75491 Segment Driver chips and two
SN75492 Digit Driver chips, each for the
LED display composed of two pre-configured LED-modules
DIS95) are based on the
TIL360 arrays and soldered directly to
the PCB. The remaining components on the PCB are mainly used to generate the
necessary supply voltage of the TMS0103 and its clock signal for the internal
The keyboard is clearly identified as a standard Klixon™ product manufactured by Texas Instruments. The color of the housing, the LED-modules and some other details like the rubber feet are known from the Datamath calculator.
A similar calculator was sold by Longines Symphonette with the Electronic Calculalator and by Radio Shack with the EC-200.
Don't miss the rare TXI-8661A based on the Exactra 23 calculator.
Datamath™ and Klixon™ are trademarks
of Texas Instruments.
If you have additions to the above article please email: firstname.lastname@example.org.
© Joerg Woerner, December 5, 2001. No reprints without written permission.