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Calculators: Handheld: Casio Memory-8R (aka Y-811)
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Size (approx): | 148mm x 72mm x 23.8mm(max)
(w,h,d) Weight 114g excluding batteries |
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Power: |
3V DC, 2 x AA size batteries. It accepts an adapter (AD-2S, 0.2W) through a socket on the top side to the far left. Battery life is quoted as 9.5 hours for manganese dry, 21 hours for alkaline. | |
| Case: | Horizontal format two-piece case in dark brown and light beige smooth plastic which is slightly wedge-shaped. The display area is raised and tilted slightly. The neutral display filter gives a clean bright image of the numbers and has two raised ridges that are printed white. A small inset panel houses a metallic label with reversed out company name and model number. An inset keyboard surround of brushed aluminium with typical Casio key frames. They keys are medium travel, squishy feel but work well. The back has another recess labelled "name" to place your own sticker. | |
| .Display: | 8 digit blue VFD, with no ninth digit for additional display. | |
| Features: | 4 function calculator with percentages and a one function memory | |
| Age: | 1975 | |
| Manufacturer: | Casio Computer Company Ltd. Made in Japan, serial No. 5607824 (on battery cover) and 4502866 on the inside of the battery compartment. | |
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Comments:
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One of a range of early, solidly built horizontal calculators by Casio. This design with some variations was used for a range of similar calculators so it is best to differentiate them with the model number if available. Sound logic but annoying seven digit negative numbers, lack of overflow recovery and negative zero bug. The original case is soft black plastic with open top and half-moon cut-outs on the front and back. It is embossed with Casio on the front and Made in Japan on the back. |
| Components: | 1 x cpu: Hitachi HD3691 5J 23
(1975), 28 pin DIL, 0.6" width 1 x 8 digit VFD display single glass tube; E6535A 4K2K 2 x transistors 5 x diodes 8 x capacitors 2 x SIL resistor arrays 4 x resistors 1 x transformer; TDK CD-1009 1G |
| Boards: | The keyboard board (ref C8A-E4A) is attached to the front with five screws and to the floating cpu board (ref C8A-1B) via twelve strong wires. |
| Construction: | Despite the screw in the battery compartment this one is very difficult to open. I would advise against it for fear of damaging you calculator; my example has numerous screwdriver marks on the case joint. However, if you really must, I found the best way was to pop the lugs on the left hand side first, there being one on the top, one each side and three on the bottom. The rear lifts away eventually. |
| Logic comments: | The (C) button is used to clear last entry of a number and the (AC) to clear the whole calculator |
| Overflow on number input is suppressed, typing in a nine digit number ignores the ninth digit | |
| An overflow error is flagged with the no answer just "E." in the first (right most) digit and is not recoverable | |
| Divide by zero results in "E." being displayed in the first (right most) digit and is not recoverable | |
| There is selectable constant on multiple and divide only by double pressing the function; i.e. (5)(X)(X)(4)(=) gives "20", (=) gives"100" | |
| Negative numbers are shown by a "-" in the immediate left digit but as there is no ninth digit you are limited to seven digit negative numbers | |
| The memory is an automatic accumulation memory only. Every time you hot (=) the result is added to memory. Use (MR) to recall and (AC) to clear | |
| This calculator suffers the negative zero bug; try (1)(-)(2)(=) to give "-1" then (+)(1) will give "-0" |
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The manual measures 85mm by 66mm and is 16
printed pages in black only. It is fan-fold configuration so that the
whole thing opens up to one long strip.
In English language only there are quite a few examples and specifications. Printed in Japan. |
