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
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|
|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:
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: email@example.com.
© Joerg Woerner, December 29, 2002. No reprints without written permission.