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Calculators: Handheld: Casio 805-MR
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Size (approx): | 98mm
(max) x 160mm x 35mm (max) (w,h,d) Weight 222g excluding batteries |
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Power: |
6V DC, 4 x AA size battery, 0.25W. Also accepts adapter (AD-4145) through top side socket on the left. | |
| Case: | A two-piece white and very black, smooth and matt, plastic case. Solidly built desktop sized calculator that just about fits in the hand. A tilted and raised neutral display filter is bordered by two printed white lines. The brushed aluminium keyboard (which wraps around the lower section) surround has printed black test for the make and model number and switch labels. The large keys are long travel squishy type with a hollow sound. | |
| Display: | 8 digit blue VFD with a ninth digit that is never used | |
| Features: | Basic four function with percentages, square root and three function memory. An extra slide switch selects between floating decimal point and fixed 2-point with round down (cut ) or round up/down (5/4). | |
| Age: | est. 1976 | |
| Manufacturer: | Made in Japan. Casio Computer Co Ltd. Serial number 5599322 on sticker inside the battery compartment | |
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Comments:
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Just about fits in the hand - probably more designed as a small desk top calculator. Allows negative square roots and only handles seven-digit negative numbers which lets it down a bit. I quite like the "cycling number" display in calculations - it make it look much more complicated! |
| Components: | 1 x cpu: NEC uPD977C R66419, 28
pin DIL 0.6" width 1 x 9 digit VFD display; single glass tube, round faced; E6532A 2 x transistors 5 x diodes 8 x capacitors 4 x resistors 2 x resistor arrays 1 x transformer; 3Y CD-1005 TDK |
| Boards: | The keyboard assembly (C8H-E4B) is attached to the front with fours screws. A set of 15 strong copper wires join it to the main cpu board (C8I-1A) which sits loosely on some plastic posts. There is a small piggy-back board transformer module on the main cpu board. |
| Construction: | Remove the single screw from the back and the one inside the battery compartment. The back section will lift off after a bit of gentle persuasion - hinge it from the top where the power socket sits. |
| Logic comments: | The (C) button is used to clear entry of a number the (AC) button to All-Clear. |
| Overflow on number input is suppressed, typing in a ninth digit is ignored. | |
| Divide by zero shows "E." in the far right (first) digit and is not recoverable. | |
| Overflow just shows "E." in the far right (first) digit and is not recoverable. | |
| There is constant on multiply and divide by pressing the operator key twice. There is no constant on plus or minus. | |
| Negative square roots are allowed | |
| There is no indication of memory store - you have to remember it! | |
| Negative numbers are flagged by a "-" sign in the immediate left hand digit but do not carry to the ninth so only seven digit negative numbers are allowed. | |
| This calculator has the negative zero bug; try (1)(-)(2)(=) which gives "-1", then try (+)(1)(=) and it shows "-0" |
