Texas Instruments TI-1250 (Repair Label)

Date of introduction:  August 1975 Display technology:  LED-stick
New price:  $24.95 Display size:  8
Size:  5.5" x 2.8" x 1.4"
 138 x 70 x 35 mm3
Weight:  3.9 ounces, 110 grams Serial No:  n.a.
Batteries:  9V  Date of manufacture:  Factory repaired wk 50 year 1975
AC-Adapter:  AC9180 Origin of manufacture:  USA (LTA)
Precision:  8 Integrated circuits:  TMS0952, TMS0972
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner
    Download manuals:   (US: 3.1M Bytes)
  (US: 2.5M Bytes)
  (EU: 3.5M Bytes)

Texas Instruments introduced the TI-1200/TI-1250 in 1975, right at the beginning of the Calculator War. Prized in 1975 still around US $25, or about $80 in 2000's money and a whooping $120 in 2020's money, these basic calculators were not yet considered to be commodities and Texas Instruments consequently repaired them. We feature this repaired TI-1250 due to its special label on the backside of the calculator that omits the serial number and country of manufacturing.

Dismantling the featured TI-1250 with Repair Date code 505 (December 1975) and manufactured around July 1975 in Lubbock, Texas reveals a very efficient and cost-optimized design with a single-sided printed circuit board (PCB) centered around a TMS0952 single-chip calculator circuit based on the TMS1000, the World's first Microcomputer and shows some obvious signs of repair.

The TMS0952 was soon replaced with the TMS0972, a pin-compatible design dropping the additional resistors and capacitor and further reducing the manufacturing costs of the TI-1250 series.

Learn more about the evolution of the TI-1250 between June 1975 and its discontinuation in 1977.

Learn more about the different Product Labels used with the TI-1250 - here at the Datamath Calculator Museum we classify the featured TI-1250 as Hardware Version 1, PCB Type 1 and Product Label Style 5, Repair Label.


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Joerg Woerner, June 29, 2021. No reprints without written permission.