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Calculators: Handheld: Elka 103 (yellow)
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Size (approx): | 70mm
x 135mm x 30mm (max) (w,h,d) Weight 122g excluding batteries |
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Power: |
6.0V DC, 4 x AA size batteries. Also accepts an adapter (undefined) through a socket on the top side to the far right. The battery compartment has a green ribbon to aid battery removal. | ||
| Case: | Lovely solid yellow-backed calculator with smooth rear and matt black front piece. Metal panel with black printed text round the switch, in its own recess. Back top of calculator is raised by about 30 degrees and the orange display filter raised even more with a "fine-line" design. This, however, lets in a lot of ambient light so reduces the contrast of the display. The lower front edge has the brand and model number printed in white. The keys are squishy, medium travel and work well enough. | ||
| Display: | 8 digit red LED with bubble lens and ninth digit for negative and memory indicators | ||
| Features: | Four functions with percentages, square root and four function memory. | ||
| Age: | This one is 1975 but the design goes back as far as 1973. | ||
| Manufacturer: | Produced by ISOT, exporter: ISOTIMPEX. Made in Bulgaria. The serial number sticker is missing on my example. | ||
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Comments:
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Lovely solid calculator, especially for its age. Not many came from Bulgaria so this is a nice example of using cheaper labour zones during the price wars of the 70s. The logic is quite good with full recovery but let down by the pseudo fixed decimal bug and negative square roots. |
| Components: | 1 x cpu: Rockwell A5502PA 7540
(week 40 of 1975) 42 pin DIL, 0.6" width 1 x nine red LED display with bubble lens 6 x transistors 4 x diodes 16 x resistors 5 x capacitors 1 x transformer TP024 |
| Boards: | Small cpu board is connected to the full sized keyboard and display board by 23-way ribbon cable. Board are secured using the case fixing screws. |
| Construction: | Remove the four screws on the back. Two of these screws are hidden underneath the sticky "model number" label. The case easily separates. |
| Logic comments: | (C) cancels an incorrect numerical entry, pressing a second time (C) clears the calculator |
| Input overflow is suppressed; keying in a ninth digit is ignored | |
| It has automatic constant on all four functions | |
| Overflow shows the result with all decimal points alight and is recoverable using (C) | |
| Divide by zero shows "0.0.0.0.0.0.0.0." and is recoverable using (C) | |
| Negative numbers are shown with a “-“ in the far left (ninth) digit thereby allowing full eight digit negative numbers | |
| Square roots of negative numbers are allowed and result in a negative number | |
| Memory storage is flagged by the decimal point of the far left (ninth) digit | |
| Using the memory is a two-keystroke sequence. To add to the memory key in (M)(+), to recall (M)(=) etc. | |
| It suffers the pseudo fixed decimal bug: key in (1)(+)(.)(0)(0)(0)(=) to give “1.000” which remains a fixed three digit decimal number until more digits are required or you use multiply or divide |
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