DATAMATH CALCULATOR MUSEUM
Texas Instruments T-1220 distributed by True Value
|Date of introduction:||1976||Display technology:||LED-stick|
|New price:||$9.95||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:||A 226135|
|Batteries:||9V||Date of manufacture:||wk 23 year 1976|
|AC-Adapter:||AC9180||Origin of manufacture:||USA|
|Program steps:||Courtesy of:||Joerg Woerner|
Texas Instruments introduced the TI-1200 in March 1975 and followed within just a few months with the TI-1250 featuring a 4-key Memory and a [CS] or [+/-] key. The TI-1200/TI-1250 family developed into one of TI's most successful calculator series, selling millions and millions units not only under its own name plate but branded for different companies like HEMA, Koh-I-Noor Hardtmuth, True Value Hardware Stores, Zayre Corporation and Western Auto.
Maybe there is a story behind this calculator - and its TI-1250 based sibling T-1225? One source (The National Museum of American History's Chip Collection, Comments by Bill Heye, Ralph McCullough) tells us that this calculator was planned as a regular TI product. Shortly after approval of the calculator by the QRA the project was stopped.
The box of the T-1220 proudly states: Custom model manufactured for True Value Hardware Stores.
The warranty address on the back of the calculator is: Texas Instruments Service Facility. Later T-1220 models removed this text.
Dismantling the featured
T-1220 calculator with
Date code 2376 LTA and manufactured in June
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.
The TMS0952 used with the original TI-1200/TI-1250 was soon replaced with the TMS0972, a pin-compatible design dropping the additional resistors and capacitor and further reducing the manufacturing costs of the calculators.
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 T-1220 as
Hardware Version 3, PCB Type 2 and Product Label Style 4, A-Series 6-Digit.
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© Joerg Woerner, December 5, 2001. No reprints without written permission.