Texas Instruments TI-1250 (Version 4)

Date of introduction:  April 1977 Display technology:  LED-stick
New price:   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:  A 1588990
Batteries:  9V  Date of manufacture:  wk 18 year 1977
AC-Adapter:  AC9180 Origin of manufacture:  USA (LTA)
Precision:  8 Integrated circuits:  TMS0972
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner
    Download manuals:   (US: 2.5M Bytes)
  (EU: 3.5M Bytes)

The final step of cost reduction of the TI-1200/TI-1250 family was introduced just a few months before its discontinuation and included a smaller encapsulation of the TMS0972 Chip.

Dismantling the featured TI-1250 with Date code 1877 LTA and manufactured in May 1977 in Lubbock, Texas reveals a very efficient and cost-optimized design with a single-sided printed circuit board (PCB) centered around a TMS972 single-chip calculator circuit based on the TMS1000, the World's first Microcomputer.

While the original design of the TMS0972 was using a 0.6 wide 28-pin DIP (Plastic Dual In-line Package with a 0.1 / 2.54 mm lead pitch) encapsulation, switched the final design of the TMS0972 to a 0.4 wide 28-pin SPDIP (Shrink Plastic Dual In-line Package with a 0.07 / 1.778 mm lead pitch) encapsulation.

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

Preparing our DCM-50A Platform to allow the Characterization of Single-Chip Calculator Circuits of the TMS0970/TMC0900 Family, we studied a TI-1200 (Version 3) calculator manufactured in October 1976 and a TI-1250 (Version 4) calculator manufactured in August 1977.

Learn more about the different Product Labels used with the TI-1250 - here at the Datamath Calculator Museum we classify the featured TI-1200 as Hardware Version 4, PCB Type 3 and Product Label Style 4, A-Series.


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Joerg Woerner, June 28, 2021. No reprints without written permission.