Texas Instruments TI-1790 DATACHRON

Date of introduction:  January 5, 1978 Display technology:  LCD (yellow)
New price:  $50.00 Display size:  8
Size:  5.3" x 2.6" x 0.4"
 136 x 67 x 11 mm3
Weight:  3.2 ounces, 88 grams Serial No:  71571
Batteries:  2*LR44 Date of manufacture:  mth 03 year 1978
AC-Adapter:   Origin of manufacture:  Japan
Precision:  8 Integrated circuits:  Toshiba T3566
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

TI-1790_Back.jpg (176458 Byte)With the TI-1790 DataChron Texas Instruments introduced a calculator combined with a clock, alarm-time and stopwatch function. Together with the stylish metal housing and the leather wallet it was a "must have" of 1978.

TI-1790_IC.jpg (274647 Byte)TI-1790_PCB.jpg (312866 Byte)Disassembling the TI-1790 reveals a smart construction and a very clean layout. The Toshiba T3566 single-chip calculator circuit, a tiny crystal for the timekeeper and a small buzzer are the components you'll notice on the printed circuit board (PCB) manufactured by an unknown supplier.

A more or less identical product was soon available with the "DATACHRON" logo printed on the front of the housing, the backside of this edition states TI-1790-II. Later a similar clock and stopwatch calculator was sold with the TI-1788 III. Don't miss the PS-9100 Jot-it Appointment Reminder introduced 15 years later.

A perfect copy of this calculator was sold in the former GDR (German Democratic Republic - Eastern part of Germany) as MR411 and later MR413.

Toshiba? Compare this calculator with the Toshiba LC-833WA. Another approach to combine a calculator with a clock could be found with the LC-831W and Olympia HIT 2000.

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If you have additions to the above article please email:

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