DATAMATH CALCULATOR MUSEUM |
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 |
Memories: | |||
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 the manufacturing 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.
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, May 29, 2021. No reprints without written permission.