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Calculators: Handheld: Adler 81C
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Size (approx): | 75mm x 120mm x 20mm (w,h,d) Weight 134g excluding batteries |
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Power: |
6V DC, 4 x AAA size battery. Also accepts adapter (undefined) through a socket on the bottom side to the far right. The socket is 2mm jack-plug, centre negative. | ||
| Case: | Square case with back and sides made of one piece of brushed aluminium. Black plastic calculator body slides down nearly half way to reveal battery compartment. Pronounced ridges on the side to aid grip. Squishy but positive action keys and silver printed labels for the switches. The brand and model number is on a black printed metallic label in its own recess. The brand is also printed with white text on the top side. The green plastic display filter is inset and tilted to give a clean bright display. | ||
| Display: | 8 digit green VFD with a ninth digit for error and negative indication | ||
| Features: | 4 function calculator with percentages, change sign and four function memory with automatic switched summation. Switched floating/fixed decimal point selection. | ||
| Age: | 1975 | ||
| Manufacturer: | TA Vertriebs GmbH, D8500 Nurnberg, Germany. Type EC 23B, Serial No. 68.793.592 | ||
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Comments:
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Unusual slide out design clear display and weighty quality-feeling calculator. Button colours are a bit of a jumble but floating decimal and summation switches are a bonus. The logic is quite robust with good recovery if a little archaic with semi-RPN input and input overflow. Black plastic case is open topped, rigid front and back and has collapsible edges. |
| Components: | 1 x cpu: NEC PD947C R55256, 28 pin
DIL, 0.6" width black plastic 1 x 9 digit VFD flat face single tube display: Futaba 5H (August 1975) 2 x transistors 9 x diodes 7 x capacitors 2 x resistor arrays 7 x resistors 1 x transformer: Zebra DCT-10 |
| Boards: | The keyboard assembly (GICO GK135-10J K-2 81C) (GICO 50.9.12 - date code 12th September 1975) sits on top of the battery compartment and main cpu (81C-C) board. They are joined by 16 strong short wires. The whole assembly sits loose, held in place by the battery terminal connections. |
| Construction: | Slide the back off as if to change the batteries then continue sliding whilst slight prizing out the metal edges. Remove the two screws on the sides and use the lever points to remove the front. |
| Logic comments: | The (Cl) button is used to clear last entry of a number and (C) to clear the whole calculator |
| The logic is semi-RPN (or algorithmic), to work out 3-2 key in (3)(+)(2)(-) to give "-1" | |
| Overflow on number input is not suppressed, typing in a nine digit number results in a "C" in the ninth digit, but it is recoverable using (Cl) | |
| An overflow shows the result and "C" ("E" if negative) in the far left ( ninth) digit and is recoverable using (Cl) | |
| Divide by zero results in zero and "C" in the far left ( ninth) digit and is not recoverable | |
| There is automatic constant on multiply and divide only | |
| Negative numbers are flagged by a "-" sign in the ninth digit thereby allowing full eight digit negative numbers | |
| The change sign (-) key can be used in mid number entry but not before | |
| Memory store is indicated by the decimal point of the far left (ninth) digit | |
| Overflow n memory shows zero with "C" in the far left ( ninth) digit which is not recoverable and the memory retains the original number | |
| There is an automatic memory summation function with the "å" key when switched on any result of an equals key is added together in the memory | |
| You can choose between floating [F] or fixed 2/3 digit decimal mode | |
| No other bugs |
