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

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:

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".

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

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