Montgomery Ward P100 aka TXI-8661A

Date of introduction:  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:  47X-17100
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

Most of the OEM-calculators developed or manufactured by Texas Instruments and sold under famous labels like Longines Symphonette, Radio Shack and Western Auto received only slight modifications to the original design. We know the odd keyplates used 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 TI-2500 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 P100. We discovered the roots of the P200 and P300 based on the electronics of the TI-2550 resp. SR-10 but using different molds for some housing parts. 

The P100 uses this approach again but carries the electronics of the Exactra 23, known as low-cost line of Texas Instruments.

TXI-8661A_2.jpg (32570 Byte)TXI-8661A_1.jpg (66307 Byte)The housing looks very similar to the Exactra calculator but got an independent design. The bottom shell of the P100 is identical to the Exactra but the upper shell uses a different LED-screen and a changed arch. The shape of the face-plate is completely different and matches the design of the P300.

Interesting to know, that the P100 molds were used again for the "electronic Wizard" M4993 distributed by Western Auto.

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If you have additions to the above article please email:

Joerg Woerner, September 20, 2002. No reprints without written permission.