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Calculators: Handheld: Decimo Vatman Extra S
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Size (approx): |
80mm
x 125mm x 20mm(max) (w,h,d) Weight 116g excluding batteries |
| Power: | 6V DC, 2 x AA size batteries. It accepts an adapter (3V DC 0.3W) through a socket on the top side to the far right. | ||
| Case: | Two piece case made from dark brown and light grey glossy plastic. The two edges and bottom are trimmed with a long black sticker. An oversized green plastic display filter wraps over the top edge and is tilted slight at the top. Just above the display is a black printed metallic sticker with the brand and model name. The very slightly recessed brushed aluminium keyboard surround has black printed text for the on switch. The small keys are squishy with a soft metallic click. | ||
| Display: | 8 digit green VFD with a ninth digit for negative, error and memory indicators | ||
| Features: | Standard four functions with percentages, change sign, pi, square root, squares, reciprocal and four function memory. | ||
| Age: | c1976 | ||
| Manufacturer: | Decimo Electronic Handy Calculator, made in Japan, serial number 10569 | ||
| Comments: | Palm-sized compact calculator with an attractive edging and plenty of basic functions. The logic is quite good with good (if unobvious) recovery and only let down by negative square roots. The original case is soft black plastic, open top with half-moon cut-outs either side. |
| Components: | 1x cpu: NEC µPD946C R5Y416, 28 pin
DIL, 0.6" width black plastic 1 x 9 digit VFD unit, single tube round face 1 x transistors 5 x diodes 6 x capacitors 7 x resistors 2 x resistor arrays 1 x transformer |
| Boards: | The main cpu board (P114055-2) sits lose on top of the keyboard assembly and is joined by 15 strong wires. The latter is attached to the front with eight screws. Access to the main board is by removal of the power socket and two of the battery terminals. |
| Construction: | Difficult to open due to the stiff case and fact that it is held together with internal lugs only. The best way I found was to locate the two lugs inside the battery compartment. Gently prize up and out the rear grey section to pop these lugs (take great care not to break this thin bit of plastic. The front section can then be prized off down the sides - and the rear lifted away. |
| Logic comments: | (CE) is used to cancel the last number entered and (C) will clear the whole calculator |
| Input overflow is not suppressed, keying in a ninth digit results in an overflow which is recoverable by dividing by ten | |
| Negative numbers are represented by a “-“ in the far left (ninth) digit thereby allowing full eight digit negative numbers | |
| There is automatic constant on all four functions | |
| Overflow shows the result with "C" (or "E" if negative) in the far left (ninth) digit and is recoverable by dividing by multiples of ten | |
| Divide by zero shows zero and "C" in the far left (ninth) digit and is not recoverable | |
| The change sign (+/-) key can be used in mid number entry | |
| Negative square roots are allowed and result in a negative number | |
| Memory store is indicated by the decimal point of the far left (ninth) digit | |
| No major bugs found |
