Montgomery Ward P8M aka TXI-8646A

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 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.

If you remember the famous Texas Instruments Datamath (TI-2500) and add a 4-key memory you would get a similar calculator to this wonderful find. There are only few calculators reported which have no direct counterpart of existing TI-products. With the P8F alias TXI-8644A and the P8P alias TXI-8645A two similar calculator without memory were sold, too.

If you dismantle this calculator, one question will arise immediately:
Was this calculator really manufactured by Texas Instruments?


 
The integrated circuit inside is not manufactured by Texas Instruments and one step ahead the TI chips of that era. The TI-2550 with similar complexity (%-key and 4-key memory) was introduced almost 6 month later. Maybe TI had a delay in the development of the TMS0601, the direct counterpart of the Western Digital LC1552 used with this P8M. 

The keyboard of the calculator is a mixture of the TI-1500 keys and the grid of the Datamath. The display board was manufactured by Texas Instruments, too. And we could proof easily: This cutie IS a Texas Instruments calculator. The answer is found in the magic number 13-04-709-478 on the printed circuit board. Read more here. With the Radio Shack EC-300 Texas Instruments used the LC1552 a second time.

Don't miss the rare TXI-8661A based on the Exactra 23 calculator.

Datamath™ is a trademark of Texas Instruments.

If you have additions to the above article please email: joerg@datamath.org.

© Joerg Woerner, December 5, 2001. No reprints without written permission.