DATAMATH CALCULATOR MUSEUM |
Western Auto Citation aka M4988 (Version 1)
Date of introduction: | May 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 |
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Weight: | 3.9 ounces, 110 grams | Serial No: | 0007284 |
Batteries: | 9V | Date of manufacture: | wk 41 year 1976 |
AC-Adapter: | AC9180 | Origin of manufacture: | USA |
Precision: | 8 | Integrated circuits: | TMS0974/ZA0355 |
Memories: | |||
Program steps: | Courtesy of: | Peter Muckermann († April 21, 2021) |
Western
Auto extended in May 1976 its portfolio of portable electronic calculators with
the M4988 aka "Citation" based on Texas Instruments'
TI-1270 to complement the
M4986 and M4987. Main differences between the M4988 and the TI-1270 are the
color of the keyplate and the missing TI logo.
Dismantling the featured
M4988 with Date code 4176 LTA and manufactured in
October 1976
in Lubbock, Texas reveals a very efficient and cost-optimized design
with a single-sided printed circuit board (PCB) centered
around a TMS0974 single-chip
calculator circuit based
on the TMS1000,
the World's first Microcomputer.
The
final step of cost reduction of the of the M4988 was introduced just a few
months before its discontinuation and included a smaller encapsulation of the
TMS0974 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-1270 between
April 1976 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 M4988 as
Hardware Version 1, PCB Type 2 and Product Label Style 3, Beige, Western Auto.
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, December 5, 2001. No reprints without written permission.