Texas Instruments TI-1250 (Version 2, Cost Reduction)

Date of introduction:  February 1976 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:  1429706
Batteries:  9V  Date of manufacture:  wk 08 year 1976
AC-Adapter:  AC9180 Origin of manufacture:  USA (LTA)
Precision:  8 Integrated circuits:  TMS0952
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner
    Download manuals:   (US: 3.1M Bytes)
  (EU: 3.5M Bytes)

The original design of the TI-1250 was only manufactured for a few months, Texas Instruments changed the PCB slightly to accommodate four additional 330Ω resistors to pull down the four keymatrix input lines of the TMS0952 Chip to VDD. We recently discovered this TI-1250 without the additional resistors populated, obviously a little measure to reduce manufacturing costs of the calculator.

Dismantling the featured TI-1250 with Date code 0876 LTA and manufactured in February 1976 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.

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 2, PCB Type 2 Cost Reduction and Product Label Style 2, 7-Digit.


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