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Texas Instruments TI-1200 (Repair Label)

Date of introduction:  March 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:  1037019
Batteries:  9V  Date of manufacture:  Factory repaired wk 27 year 1975
AC-Adapter:  AC9180 Origin of manufacture:  USA
Precision:  8 Integrated circuits:  TMS0952 or TMS0972
Memories:      
Program steps:   Courtesy of:  Joerg Woerner
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Texas Instruments introduced the TI-1200/TI-1250 in 1975, right at the beginning of the Calculator War. Prized in 1975 still around US $20, or about $65 in 2000's money and a whooping $100 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-1200 due to its special label on the backside of the calculator that omits the serial number and country of manufacturing.

Dismantling the featured TI-1200 with Repair Date code 275 (July 1975) and manufactured around May 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.

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 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-1200 series.

Learn more about the evolution of the TI-1200 between March 1975 and its discontinuation in 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 1, PCB Type 1 and Product Label Style 5, Repair Label.

 

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If you have additions to the above article please email: joerg@datamath.org.

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