DATAMATH CALCULATOR MUSEUM
Montgomery Ward P8F aka TXI-8644A
|Date of introduction:||August 1, 1973||Display technology:||LED-modules + lens|
|New price:||$59.50||Display size:||8|
|Size:|| 5.7" x 3.1" x 1.6"
146 x 79 x 41 mm3
|Weight:||5.1 ounces, 144 grams||Serial No:||37X-0002843|
|Batteries:||4*AA||Date of manufacture:|
|AC-Adapter:||Origin of manufacture:||USA|
|Program steps:||Courtesy of:||João Oliveira|
This neat calculator does not look like a Texas Instruments product. To identify it, you have to know more about the coding used by Montgomery Ward:
Models starting with
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.
An identical housing was used for both the P8P alias TXI-8645A and the P8M alias TXI-8646A calculators. The printed circuit board and the serial number of the calculator gives you another information: Late P8F calculators (e.g. 37X-0026077 from Thomas Brockmeier) carry a PCB with a marking P8F/P8P. Okay, the same PCB in two calculators. Please compare this serial number with the P8P: 37X-0066692. Let's assume that the P8P replaced the P8F in the year 1974 and the happy customer got the %-key for free.
Dismantling this P8F reveals another surprise: The printed circuit board (PCB) carries a magic number that links to a lot of other calculators like the Radio Shack EC-300 and EC-1000.
|The printed circuit board of the P8F
looks like most calculator based on the TMS0100 single-chip calculator
circuit. Just a LED-display, some driver circuits and a
DC/DC-converter to generate the power supply.
More important is the number etched in the PCB:
|The small display board uses
LED-modules with just one digit per module. Once again the magic
|The components side of the display
board sports the logo of Texas Instruments etched in the PCB:
13-04-709-xxx numbers were used by TI!
This calculator looks very unfamiliar compared to other Texas Instruments calculators. Notice the combined [-=] and [+=] keys not known from calculators sold by TI.
Don't miss the rare TXI-8661A
based on the Exactra 23
If you have additions to the above article please email: email@example.com.
© Joerg Woerner, December 5, 2001. No reprints without written permission.