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Unisonic LC 262

Date of introduction:  1979 Display technology:  LCD
New price:  $39.99 (SRP June 1979) Display size:  8
Size:  2.2" x 3.6" x 0.30"
 55 x 91 x 8 mm3
   
Weight:  1.5 ounces, 42 grams Serial No:  4872110
Batteries:  2*LR43 Date of manufacture:  year 1979
AC-Adapter:   Origin of manufacture:  Taiwan
Precision:  8  Integrated circuits:  Mitsubishi  M58490P
Memories:  3    
Program steps:   Courtesy of:  Joerg Woerner
    Download manual:   (US: 2.2 MByte)

National Semiconductor introduced already in 1978 with the NS103 Data Checker an electronic record keeper with three continuous memories to track bank and charge account balances with dedicated keys:

Memory 1 [CHK] [DEP] [BAL] [A]
Memory 2 [PMT] [CHG] [BAL] [B]
Memory 3 [PMT] [CHG] [BAL] [C]
Total sum of Memories [GT]

While the NS103 Data Checker was based on proprietary technology, introduced NEC of Japan with the uPD1833G in 1980 a single-chip calculator circuit that created the blueprint for checkbook-sized Account Manager calculators and thereupon the market got swamped with products based on this design. The uPD1833G simplified the use of the memories by removing the redundant [A], [B], and [C] keys and replaced the inconvenient three-way power-switch of the NS103 Data Checker with two dedicated [ON] and [OFF] keys and a [DS] key to toggle between two entry modes:

Indicator (--) Floating decimal with manual insertion of the decimal using the [.] key
Indicator (AM) Add mode with the decimal automatically put in the dollars and cents position (0.00)

Even the successor of the NS103, known as NS103A, switched its internals to the uPD1833G but we feature some more Account Manager calculators in the Datamath Calculator Museum based on this technology:

Canon Checkbook - Missing the Toggle Key for the decimal mode
Royal LCB 841 - The Art of Perfection in Japan
Royal LCB 835 - Just one Memory (uPD1831G)
Texas Instruments TI-2200 Checkwriter - Late, but not too late
This Unisonic LC 262CK Check Master - Credit Card sized

NEC of Japan lost some market share with their design for Account Manager calculators in the Eighties, when competitors like Hitachi and Sharp introduced similar chips and finally lost the business completely to Toshiba's "Solar Cells" compatible design. Find more Account Manager calculators in the Datamath Calculator Museum:

Canon Checkbook II - Toshiba inside
Casio CB-80 - Hitachi inside
Unisonic LC 224CK Check Master - Sharp Inside
Texas Instruments TI-2200 II Checkwriter - Toshiba + Solar cells = Winning formula

Dismantling the featured LC 262 manufactured in 1979 in Taiwan reveals a clean design centered around a Mitsubishi  M58490P single-chip calculator circuit soldered on a double-sided printed circuit board (PCB) and powered by two small LR43 batteries.

Inspecting the PCB of this LC 262 manufactured in 1979 brought our attention to a small mark reading 203-3, most likely a reference to Type 203 and Revision 3 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.

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: This 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: LC 226CK, 1 Memory, Thailand

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 13, 2020. No reprints without written permission.