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Unisonic LC 266CK Checkbook Balancer

Date of introduction:  1987 Display technology:  LCD
New price:   Display size:  8
Size:  2.8" x 6.1" x 0.25"
 70 x 154 x 7 mm3
   
Weight:  2.5 ounces, 72 grams Serial No:  
Batteries:  LR54 Date of manufacture:  year 1987
AC-Adapter:   Origin of manufacture:  Taiwan
Precision:  8  Integrated circuits:  Toshiba T7752S
Memories:  3    
Program steps:   Courtesy of:  Joerg Woerner

Unisonic entered the market of Checkbook Calculators with the LC 262 in 1979. It features Account Manager functionality with three permanent (till you remove the batteries) Memories and started a very successful product line. We discovered as of now ten different family members:

1979: LC 262, 3 Memories, Credit Card size
1981: LC 262CK, 3 Memories, Credit Card size
1981: LC 263CK, 3 Memories
1981: LC 224CK, 1 Memory
1982: LC 224CKE, 1 Memory, Pen
1983: LC 224CKM, 1 Memory, Pen
1983: LC 223CK, 1 Memory, Credit Card size
1985: LC 225CK, 1 Memory
1987: This LC 266CK, 3 Memories, Taiwan
1988: LC 226CK, 1 Memory, Taiwan
1990: LC 226CK, 1 Memory, Thailand

Dismantling the featured LC 266CK manufactured in 1987 in Taiwan reveals a clean design centered around a Sharp LI3330MT single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) and powered by two LR54 batteries. The similar LC 225CK was introduced around 1985 and sports a different color scheme.

Inspecting the PCB of this CBC 80NT manufactured in 1987 brought our attention to a small mark reading 308-16, most likely a reference to Type 308 and Revision 1.6 of the design (schematics and layout). We noticed the PCB-Mark 308 during our research on the PCBs of a lot of more or less identical Account Managers, find an overview of the OEM brands/models here.

Please find an overview of the PCB-Marks we discovered so far on Account Manager calculators.

Learn more about single-chip calculator circuits used in Account Manager Calculators.

Don't miss the Corvus CheckMaster introduced by Mostek already in 1975. This rare product retains the balance of your memory even when shut off but uses power-hungry electronics.



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

Joerg Woerner, February 27, 2020. No reprints without written permission.