Texas Instruments TI-1200 (Version 3, Style 3)

Date of introduction:  March 1976 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:  1975401
Batteries:  9V  Date of manufacture:  wk 17 year 1976
AC-Adapter:  AC9180 Origin of manufacture:  USA (LTA)
Precision:  8 Integrated circuits:  TMS0972
Program steps:   Courtesy of:  Joerg Woerner
    Download manuals:   (US: 1.3M Bytes)
  (EU: 3.5M Bytes)

The TMS0952 introduced with the original design of the TI-1200 and TI-1250 was soon replaced with the TMS0972, a pin-compatible design dropping the additional resistors and capacitor and further reducing themanufacturing costs of the TI-1200 series.

Dismantling the featured TI-1200 with Date code 1776 LTA and manufactured in April 1976 in Lubbock, Texas reveals a very efficient and cost-optimized design with a single-sided printed circuit board (PCB) centered around a TMS0972 single-chip calculator circuit based on the TMS1000, the World's first Microcomputer.

Early calculators of the TI-1200 and TI-1400 family use a keyboard with a 6*4 matrix having only 5 key-dome rows populated for a total of 20 keys. The unused key is hidden with the metal faceplate and removing it would add the missing [CS] or [+/-] key. Later the keyboard was cost-optimized to a 5*4 matrix. Find two of them in the Speak & Spell introduced in the year 1976.

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. While the original design 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 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-1200 between March 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-1200 - here at the Datamath Calculator Museum we classify the featured TI-1200 as Hardware Version 3, PCB Type 2 and Product Label Style 3.


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