DATAMATH CALCULATOR MUSEUM |
Western Auto Citation aka 66-4988-3
Date of introduction: | 1977 | Display technology: | Fluorescent |
New price: | $14.99 | Display size: | 8 |
Size: | 5.4" x 2.8" x
1.3" 138 x 72 x 32 mm3 |
||
Weight: | 3.5 ounces, 98 grams | Serial No: | |
Batteries: | 9V | Date of manufacture: | wk 16 year 1978 |
AC-Adapter: | AC9180 | Origin of manufacture: | El Salvador |
Precision: | 8 | Integrated circuits: | TMC0921 |
Memories: | 1 | ||
Program steps: | Courtesy of: | Joerg Woerner |
With the discontinuation of the TI-1200 family in 1977, Western Auto consequently replaced the M4988 "Citation" calculators and its siblings M4986 and M4987 with products based on the TI-1000 family. While the backside of the revised "Citation" calculator is missing any reference to the previous M4988 designation, sports the sales box a part number 66-4988-3, obviously a reference to the original naming scheme. Please find in the table below a cross reference between Western Auto's 1976/1977 and 1977/1878 calculator offerings:
Western Auto 1976/1977 |
Texas Instruments 1976/1977 |
Western Auto 1977/1978 |
Texas Instruments 1977/1978 |
Citation M4986 |
TI-1200 | Citation 66-4986-7 |
TI-1000 |
Citation M4987 |
TI-1250 | Citation 66-4987-5 |
TI-1025 |
Citation M4988 |
TI-1270 | Citation 66-4988-3 |
TI-1050 |
The
elegant design of the TI-1270 based M4988 "Citation" calculator was
continued with its successor and further enhanced with a two-tone keyplate. Other than that are the "Citation"
and TI-1050 identical, the back side of the calculators
tells you even its manufacturer Texas Instruments.
Dismantling
the featured 66-4988-3 with Date code 1678 and manufactured in
April 1978
in El Salvador reveals a very efficient and cost-optimized design
with a small double-sided printed circuit board (PCB) centered
around a TMC0921 single-chip calculator
circuit and powered by a 9V battery.
The TMC0920
calculator chips are minimalistic designs sporting just 512*9 Bits of ROM
(Read-Only Memory) and 200 Bits of SAM (Serial-Access Memory) organized in 5
Registers of 10 Digits, each but feature both an integrated charge pump driver
to generate the high voltage (around -22V) for the Anodes and Grids of the
VF-Display and integrated drivers for the Filament (heater) of it. Additional
cost savings could be achieved by replacing a conventional [ON-OFF] switch with
a simple push-button [ON] key.
Western Auto Supply Company ceased end of 1978
distributing "Citation" calculators manufactured by Texas Instruments, just 5
years after their journey began with the M4995
"electronic Wizard".
If you have additions to the above article please email: joerg@datamath.org.
© Joerg Woerner, December 29, 2002. No reprints without written permission.