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Calculators: Handheld: Novus 831
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Size (approx): | 70mm x
138mm x 24mm (max) (w,h,d) Weight 62g excluding batteries |
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Power: |
9.0V DC, 1 x PP3 size battery. Accepts an adapter/charger (undefined) through a socket on the left side, about half way up. | ||
| Case: | The two-piece buff case has rounded edges and is very lightweight. An extra stuck on keyboard surround panel is printed in brown and a slightly tilted red display filter makes the best of the small LEDs. The small keys are short travel loud click type, my example suffers bounce a bit. | ||
| Display: | 8 digit red LED with bubble lens and a ninth digit for negative indication | ||
| Features: | Standard four functions with percentages, squares and square root | ||
| Age: | est. 1977 | ||
| Manufacturer: | No markings on this model and no serial number. | ||
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Comments:
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Cheap feeling calculator under the brand name by National Semiconductor. The rounded edges and the four assembly screws are the only things that help it. Lack of recovery is a nuisance but otherwise sound logic. Very early version of the chip surface mounted and resin covered. |
| Components: | 1 x cpu: chip mounted on board
covered by resin 1 x 9 digit red LED display |
| Boards: | The keyboard board is fixed to the front with 34 plastic rivets and fixes to the main cpu board via 17 strong wires. The cpu board (ref: Nat Semi M830 51A) is just about big enough to hold the display and IC. |
| Construction: | Remove the four screws and the back lifts off. |
| Logic comments: | The (CE/C) key is used to cancel an entry whilst a second press clears the whole calculator |
| Input overflow is suppressed inputting an ninth digit is ignored | |
| Negative numbers are shown with a "-" to the immediate left of a number travelling into the fare left (ninth) digit thereby allowing full eight digit negative numbers | |
| There is automatic constant on all four functions | |
| Divide by zero shows ".0.0.0.0.0.0.0.0." and is not recoverable | |
| Overflow shows the result with all decimal points alight (including the far left ninth digit) and is not recoverable | |
| Oddly, the decimal point is not alight when you input a number | |
