About older Casio Calculators

Appendix to the article
Ray Mackay


Attached please find a couple of line drawings covering the 'Older Casio' models. The author does not have illustrations of these models only Schematics and line drawings. The information is posted so that people intereseted in the subject can evaluate the information and see if it may be of future beneficial use to the 'calculators collective'. Early desktop Casio calculator model 121-161. Uses discrete transistor logic consisting of a a row of flip-flops. The data cycles through an adder. A nixie tube type display is clocked to display the data relying on residual intensity to keep the display visable to the next cycle. Has no memory, as such, the flip-flops hold the data. Typical of the period (Circa June 1969).

Casio CM-603 ON THE LEFT Circa Apr 1973. Portable. Also sold as the Remington 663. Battery operated (giving about six hours on four UM-3 Batteries, or AC operated, this calculator uses the traditional discrete seven segment display plus a decimal point (the tube operating like an anode valve with a heater filament). The microPD LSI (µPD usually indicates it was made by NEC) drives the segments of the display fromn S1 through S8 Digits 1 through 6 were also driven by the CPU through an inverter IC T3144 (Toshiba ?).

The Mini Delux Illustrated below was a generic D-73D-X001 later renamed the DX-73D was a smallish calculator for the period. Battery Operated (4 X UM3) it could also be mains driven through an A/C adaptor. The Display was a LD8105 which I refer to as a Flouro display. Basically this means the display was encapsulated in one complete glass envelope containg a filament. The wires to connect the Digital anodes and the segment wires came out of the end of the envelope for soldering to the PCB. One had to make certain one got it right the first time as once the leads were cut you were committed to the process. Using an LSI (µ970C the machine was clocked by a T3184 IC pulse generator. It was a very capable calculator as it had a left shift key to recall data off the machine it also had Total and Percentage Keys.

The R3 was an early printing Calculator that superseded the R1 (April 1971) and R2 (which was released later at an unknown date), the R3 being released in June 1972. It was an LSI operated calculator. Processor CPU's were HD 32101P : HD 32103P : HD 3213P and Memory Chips HN3255P & HN3207P (origin unknown) HD Usually indicated Hitachi. It used quite a lot of discrete IC gates and the data was clocked through memory registers and an adder. Considering the year the machine could be classified as advanced for the time. It was mains operated. The display was a flouro type display drive by two separate LSI's also HD (Hitachi sourced chips). The printer mechanism was driven by buffering chips HD3219P. The generic number was A12L-2.E2 which was a departure for the usual AX number although it was also listed as a DX29.

Disclaimer...This material is provided for evaluation purposes only. Copyrights, if they exist are aknowledged as belonging to Casio. The material may only be used for educational and historic purpose. Reproduction for profit is strictly prohibited. 

Copyright © January 1998 Ray Mackay All rights reserved ® 1998


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Updated June 21, 2004