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Bedol Checkmaster Standard (with Leather Bi-Fold Cover)

Date of introduction:  2000 Display technology:  LCD
New price:  $68.00 (SRP July 2020 w/ Leather) Display size:  8
Size:  2.8" x 5.9" x 0.35"
 71 x 151 x 9 mm3
   
Weight:  3.2 ounces, 90 grams Serial No:  
Batteries:  CR2025 Date of manufacture:  mth 07 year 2000
AC-Adapter:   Origin of manufacture:  China
Precision:  8  Integrated circuits:  unknown
Memories:  3    
Program steps:   Courtesy of:  Ken H. Meine
    Download manual:   (US: 4.4 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
This Royal LCB 835 - Just one Memory (uPD1831G)
Texas Instruments TI-2200 Checkwriter - Late, but not too late
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
This Unisonic LC 224CK Check Master - Sharp Inside
Texas Instruments TI-2200 II Checkwriter - Toshiba + Solar cells = Winning formula

Dismantling the featured Bedol Checkmaster Standard Checkbook Calculator manufactured in July 2000 in China reveals a clean design centered around an unknown single-chip calculator circuit bonded on a double-sided printed circuit board (PCB) and powered by 8 solar cells and a CR2025 (3 Volts) Lithium backup battery. At first glance you would expect a Toshiba T7752S chip under the black epoxy blob but we suspect a copy of the original design for two reasons:

All known T7752S based designs use 4 solar cells and a 1.5V backup battery instead the 8 solar cells and 3V battery
The T9952S is packaged in a 60 pin housing with 46 traces connected on the PCB while we count 56 traces leaving the epoxy blob

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

Bedol entered the market of Checkbook Calculators with the Checkmaster Standard in 2000. 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 sixteen different family members:

2000: Checkmaster Standard, 3 Memories
2000: This Checkmaster Standard w/ Leather Cover (5 options), 3 Memories
2000: Checkmaster Gold, 3 Memories, Time, Alarm, Calendar, Currency and Metric conversion
2000: Checkmaster Superthin Page Marker, 3 Memories, Time, Alarm, Calendar, Currency and Metric conversion ($30.00 SRP February 2020)
2000: Checkmaster Superthin Page Marker w/Leather Cover, 3 Memories, Time, Alarm, Calendar, Currency and Metric conversion ($48.00 SRP February 2020)
2000: Checkmaster Easyrule, 3 Memories, ruler form with oval hole configuration for planners
2000: Checkmaster Easyrule Gold, 3 Memories, Time, Alarm, Calendar, Currency and Metric conversion, ruler form
2xxx: Checkmaster Standard White w/Vinyl Bi-fold Cover, 3 Memories ($30.00 SRP February 2020)
2xxx: Checkmaster Standard White w/Leather Bi-fold Cover, 3 Memories ($68.00 SRP February 2020)
2xxx: Checkmaster Standard White w/Leather Tri-fold Cover, 3 Memories ($78.00 SRP February 2020)
2xxx: Checkbook Balancer Credit Card Calculator, 3 Memories ($19.00 SRP February 2020)
2xxx: Checkbook Balancer Credit Card Calculator w/Bonded Leather Cover, 3 Memories ($25.00 SRP February 2020)

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, March 2, 2020. No reprints without written permission.