Texas Instruments TI-25X Solar

Date of introduction:  1996 Display technology:  LCD
New price:   Display size:  8 (5 + 2)
Size:  4.6" x 2.5" x 0.40"
 117 x 64 x 10 mm3
Weight:  1.8 ounces, 50 grams Serial No:  
Batteries:  n.a. Date of manufacture:  mth 03 year 1997
AC-Adapter:   Origin of manufacture:  China (N)
Precision:  11 Integrated circuits:  Toshiba T6974
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

This TI-25X Solar manufactured in China is identical to the US-built TI-25 STAT. In Europa the calculator was sold as TI-30S giving some memories to the very first TI-30 with a red LED-display introduced in 1976. 

Like all early TI-30 variants this TI-25X Solar uses an 8-digit display. This is for most calculations convenient but in scientific notation you'll get only 5 digits of mantissa.

Dismantling this TI-25X Solar manufactured in March 1997 by Nam Tai Electronics, Inc. in China reveals a printed circuit board (PCB) with a TI-30S designator and sporting a Toshiba T6974 single-chip calculator circuit. We know this calculator chip from some older calculators, e.g. the TI-31 Solar, the TI-35 SLR and even the TI-30 SLR introduced in 1984.

ti-25x_PCB.jpg (160150 Byte)Dismantling a TI-25 STAT from a late production run (year 2000) revealed a small surprise: The original Toshiba T6974 single-chip calculator circuit was replaced with a T6F27 chip. This gave the T6974 a life span of almost 15 years.

The similar TI-25 SOLAR lacked the statistical functions.

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If you have additions to the above article please email:

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