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Unisonic LC 226CK Checkbook Balancer

Date of introduction:  February 1988 Display technology:  LCD
New price:  $12.95 (SRP November 1988) Display size:  8
Size:  2.8" x 6.1" x 0.30"
 70 x 154 x 7 mm3		    
Weight:  2.4 ounces, 68 grams Serial No:  
Batteries:  2*LR54 Date of manufacture:  mth 08 year 1991
AC-Adapter:   Origin of manufacture:  Thailand
Precision:  8  Integrated circuits:  Sharp LI3330MT
Memories:  1    
Program steps:   Courtesy of:  Ken H. Meine
    Download manual:   (US: 0.9M Bytes)

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: LC 266CK, 3 Memories, Taiwan
• 1988: LC 226CK, 1 Memory, Taiwan
• 1990: This LC 226CK, 1 Memory, Thailand

Dismantling the featured LC 226CK manufactured in August 1991 in Thailand 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 LC 226CK manufactured in August 1991 brought our attention to a small mark reading 307-10, most likely a reference to Type 307 and Revision 1.0 of the design (schematics and layout).

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, January 15, 2020. No reprints without written permission.