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Calculators: Handheld: Nestler OH 1002A
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Size (approx): |
88mm
x 125mm x22mm (w x h x d) Weight 102g excluding batteries |
| Power: | 3.0V DC using 2 x AA size batteries. It accepts an adapter (3V DC 0.3W) through a socket on the left side in line with the (CM) key | ||
| Case: | Two-piece case in dark grey plastic with a dominant front brushed aluminium panel which wraps around the rounded top and bottom edges. This panel has black printed text for the brand, on/off switch label and designer keyboard boarder. The green plastic display filter is flat and flush. The Casio-like keys are easy to use with a soft click and individual escutcheons. | ||
| Display: | 8 digit green VFD with a ninth digit for negative, error and memory indication | ||
| Features: | Standard four functions with percentages, square root and four-function memory | ||
| Age: | 1977 | ||
| Manufacturer: | Nestler, no manufacture or country given but the label is in German, serial number 108672 | ||
| Comments: | Quality feeling calculator with good display and keys. The logic is quite sound with good recovery and only let down by negative square roots. The original case is soft black plastic with open top and half-moon cut-outs either side. It reminds me of the Prinztronic SR99M type IV that has many similarities inside as well. |
| Components: | 1 x cpu: Texas TMS1045NL 7731
(week 31 of 1977), 28 pin DIL, 0.3" width black plastic 1 x 9 digit VFD unit: single tube round face: 9-CT-10 6C (March 1976) 1 x transistor 5 x diodes 5 x capacitors 5 x resistors 1 x transformer: 567 |
| Boards: | The keyboard assembly is fixed to the front via ten screws and is joined to the main cpu board (33-424A) by a 15-way ribbon cable. The cpu board sits lose in the back. |
| Construction: | Difficult top open as it is held together by internal lugs and the plastic sides are quite stiff. There is a coin slot on the upper edge, which does not help much. Lever this edge apart with a blunt object, pushing inwards the rear section then travel down one of the sides. Eventually the front will lift off. |
| Logic comments: | The (C/CE) key is used to once to clear the last entry and a second time clears the whole calculator. |
| Input overflow is suppressed, typing in a ninth digit is ignored | |
| There is automatic constant on all four functions | |
| Negative numbers are indicated by a “-“ in the far left (ninth) digit thereby allowing full eight digit negative numbers | |
| Overflow shows the result and “C” (“E” if negative) in the far left (ninth) digit and is recoverable using (C/CE) | |
| Divide by zero shows zero and “C” in the far left (ninth) digit and is recoverable using (C/CE) | |
| Negative square roots are allowed and result in a negative number | |
| Memory store is indicated by an upper “n” in the far left (ninth) digit | |
| Overflow in memory stores the result divided by 108 | |
| No major bugs found |
