Unisonic LC-7311BK

Date of introduction:  1981 Display technology:  LCD
New price:   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:  5374901
Batteries:  2*LR54 Date of manufacture:  year 1981
AC-Adapter:   Origin of manufacture:  Taiwan
Precision:  8  Integrated circuits:  Sharp LI3033MT
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Does this Unisonic LC-7311BK calculator look familiar to you?

Dismantling the featured LC-7311BK manufactured in 1981 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 Unisonic LC-7311BK calculator brought our attention to a small mark reading MK65-6, we spotted this PCB-Mark already with near identical offspring like the IMA LC 688, NSC Novus Electronics NS220, TI-1755 and TI-1756 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-7311BK 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.

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