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IMA LC 688

Date of introduction:  1982 Display technology:  LCD
New price:  $8.99 (SRP Sep. 1982) Display size:  8
Size:  3.9" x 2.4" x 0.25"
 100 x 60 x 6 mm3
   
Weight:  1.6 ounces, 44 grams Serial No:  8571527
Batteries:  2*LR54 Date of manufacture:  year 1982
AC-Adapter:   Origin of manufacture:  Taiwan
Precision:  8  Integrated circuits:  Sharp LI3033MT
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Does this IMA (International Merchandising Associates) LC 688 calculator look familiar to you?

Dismantling the featured LC 688 manufactured around 1982 by an unknown OEM (Original Equipment Manufacturer) in Taiwan reveals a clean design centered around a Sharp LI3033MT single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) and powered by two small LR54 (LR1130) batteries.

Inspecting the PCB of this IMA LC 688 calculator brought our attention to a small mark reading MK65-A, we spotted this PCB-Mark already with near identical offspring like the NSC Novus Electronics NS220, TI-1755, TI-1756 and Unisonic LC-7311BK and suspect to locate it in the Technico MK 65, too. Plus the Asaflex MK 653, Benkson CAL-20, Levi MK 1652, MBO MK65, M-Office MK650, Olympia MK 65, Privileg Senator, Radio Shack EC-376, Satek MK 652 and Unisonic LC-7311M. Based on the PCB-Marks located with the TI-2130 and its twin Technico F-800 we are almost positive that the LC 688 and its siblings were manufactured by Inventa Electronics Corporation of Taipei, Taiwan. We started compiling a list of the PCB-Marks on calculators manufactured by OEMs for Texas Instruments.



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

Joerg Woerner, March 15, 2020. No reprints without written permission.