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Western Auto Citation aka 66-4986-7 (Version 2)

Date of introduction:  1977 Display technology:  LED-stick
New price:   Display size:  8
Size:  5.4" x 2.8" x 1.3"
 138 x 72 x 32 mm3
   
Weight:  3.0 ounces, 84 grams Serial No:  
Batteries:  9V  Date of manufacture:  wk 29 year 1978
AC-Adapter:  AC9180 Origin of manufacture:  USA (LTA)
Precision:   Integrated circuits:  TMC1992
Memories:      
Program steps:   Courtesy of:  Joerg Woerner

With the discontinuation of the TI-1200 family in 1977, Western Auto consequently replaced the M4986 "Citation" calculators and its siblings M4987 and M4988 with products based on the TI-1000 family. While the backside of the revised "Citation" calculator is missing any reference to the previous M4986 designation, sports the sales box a part number 66-4986-7, 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

Citation_1.jpg (74301 Byte)The eye-catching "woody" design of the TI-1200 based M4986 "Citation" calculator was dropped with its successor in favor of an elegant gray-white keyplate almost matching the original TI-1000 look and feel. Other than that are the "Citation" and TI-1000 identical, the back side of the calculators tells you even its manufacturer Texas Instruments.

Dismantling the featured 66-4985-7 with Date code 2978 LTA and manufactured in July 1978 in Lubbock, Texas reveals a very efficient and cost-optimized design with a flexible single-sided printed circuit board (Flex-PCB) centered around a TMC1992 single-chip calculator circuit and powered by a 9V battery.

The TMC1990 calculator chips are based on the TMS0970 used with the TI-1200 family but integrate a power latch and power transistor to replace the original sliding power switch with two more cost effective [ON] and [OFF] keys.

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".



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If you have additions to the above article please email: joerg@datamath.org.

Joerg Woerner, January 4, 2002. No reprints without written permission.