DATAMATH CALCULATOR MUSEUM
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DATAMATH CALCULATOR MUSEUM |
Texas Instruments TI-1265
| Date of introduction: | April 9, 1976 | Display technology: | Fluorescent |
| New price: | $26.95 | Display size: | 8 |
| Size: | 5.5" x 2.8" x 1.4" 138 x 70 x 35 mm3 |
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| Weight: | 4.5 ounces, 127 grams | Serial No: | A 1056444 |
| Batteries: | 9V | Date of manufacture: | wk 09 year 1977 |
| AC-Adapter: | AC9180 | Origin of manufacture: | USA (LTA) |
| Precision: | 8 | Integrated circuits: | TMS1043 |
| Memories: | 1 | ||
| Program steps: | Courtesy of: | Joerg Woerner |
Texas
Instruments introduced in March 1975 with the TI-1200 the first member of a very
successful calculator family for budget oriented customers. The design of the
TI-1200/TI-1250 was a result
of continuous cost optimization and centered around a
TMS0950 or
TMS0970 single-chip calculator circuit
driving directly a small LED display with 8 or 9 digits. This TI-1265 introduced
in April 1976 traded the red LED display for a blue-green Vacuum Fluorescent
Display (VFD) sporting not only larger and better readable digits but resulting
in a longer lifetime of the 9V batteries, too. Main disadvantages of VFDs are
the higher voltages required for its proper operation and the extra filament
circuit, resulting typically in higher manufacturing costs.
Dismantling the featured TI-1265 with
Date code 0977 LTA and manufactured in
March 1977
in Lubbock, Texas reveals indeed a much more complex design than a
TI-1250 manufactured in the same timeframe and having
similar capabilities. Instead a very efficient and cost-optimized design
with a single-sided printed circuit board (PCB) centered
around a TMS0972 single-chip
calculator circuit and no other components than an 8-digit display modules, do
we recognize:
|
•
TMS1043 single-chip
calculator circuit with integrated high voltage drivers, based
on the TMS1000
-
the World's first Microcomputer • DC/DC Converter Module to generate the high voltage (around -22V) for the Anodes and Grids of the VF-Display • ITRON 9-digit VFD Module |
The TMS1043 was used with the TI-2550
III, too and sporting even [1/x], [x2] and [√x] keys.
The Dutch department store HEMA sold an identical model as reactor
1265.
Don't miss the rare Texas Instruments 1265 manufactured for Koh-I-Noor Hardtmuth.
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-1265 as
Hardware Version 1, PCB Type 1 and Product Label Style 4, A-Series.
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, December 5, 2001. No reprints without written permission.