Western Auto Citation aka M4988 (Version 2)

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 1577 LTA and manufactured in April 1977 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.

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: