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
• TXI were produced by Texas Instruments
• DAN were produced by APF
• DNS were produced by National Semiconductors (later Novus)
• GLE by Lloyd's
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.