Montgomery Ward electronic D8F aka TXI-8647A

Date of introduction:  1973 Display technology:  Panaplex II
New price:  $89.50 Display size:  8
Size:  8.8" x 6.5" x 2.7"
 224 x 165 x 68 mm3
Weight:  28.8 ounces, 818 grams Serial No:  37X-13040
Batteries:   Date of manufacture:  wk 14 yr 1973
AC-Adapter:  120 V Origin of manufacture:  USA
Precision:  8 Integrated circuits:  TMS0109
Program steps:   Courtesy of:  Joerg Woerner

Most of the OEM-calculators developed or manufactured by Texas Instruments and sold under famous labels like Longines Symphonette, Radio Shack and Western Auto got only slight modifications to the original design. We know the odd-looking keyplates uses in some TI-1200 derivatives like the True Value T-1220 or the Western Auto M4986.

The most exciting OEM-products were manufactured for the American department store Montgomery Ward Inc. Starting with the original P800 introduced in the timeframe of the Datamath calculator and the P8 family (P8F, P8P and P8M) using a totally different housing compared to all known TI calculators we got this wonderful electronic D8F. 

This electronic D8F is obviously based on the TI-3000 and the related Radio Shack EC-1000 but sports some differences:

Calculator [K]/[C] Switch [$]/[F]/[4] Switch
TI-3000 no no
TXI-8647A yes no
EC-1000 yes yes

TXI-8647A_PCB.jpg (104188 Byte)Dismantling the electronic D8F reveals a typical Texas Instruments design of the 1973/1074 time frame based on the TMS0109 single-chip calculator circuit.

Please notice the missing switch on the small printed circuit board (PCB).

TXI-8647A_1.jpg (39701 Byte)Montgomery Wards calculators always states on the backside of the housing the manufacturer. TXI is the code for products developed by Texas Instruments.

The story of the electronic D8F doesn't stop here, Montgomery Ward introduced a series of three exciting calculators:

electronic D8F aka TXI-8647A, based on the TI-3000
electronic D10P aka TXI-8648A, based probably on the TI-3500
electronic D12K aka TXI-8649A, based probably on the TI-4000

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If you have additions to the above article please email:

Joerg Woerner, December 30, 2006. No reprints without written permission.