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Calculators: Handheld: Sharp Elsi EL-122
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Size (approx): | 87mm x 143mm x
12-40mm (w,h,d) Weight 184g excluding batteries |
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Power: |
4.5V DC, 3 x AA size batteries. Also accepts an adaptor (DC 4.5V 0.5W) through a socket on the top side to the far left. The three batteries stack in two layers which explains the wedge shape. A black ribbon-pull is provided to remove the batteries. The on/off switch is on the left hand side just above the Sharp logo. | ||
| Case: | Two piece main case in dark brown mottled plastic with two white gloss finish plastic side pieces. It is very wedge shaped making it ideal for desktop or for use in the hand. An oversized green display filter is flat and flush and gives a very bright image. Below the display is an aluminium sticker printed with red and brown text which sits in its own recess. They keys are squishy with a bit of a hollow sound but work very well to this day. There is a carry strap eyelet on the left hand side near the top, the strap being a black woven type. | ||
| Display: | 6 digit green VFD with no seventh digit but an extra red LED to indicate display shift just below. The display is left leading rather than the more normal right reading familiar today. | ||
| Features: | Four function plus display shift | ||
| Age: | 1974 | ||
| Manufacturer: | Sharp Corporation, Made in Japan. Serial number 44039206 on the rear sticker. | ||
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Comments:
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Solid feeling basic calculator that is truly twelve digit and very easy to use. Similar in design to the EL-8002. Note the early use of Elsi, rather than Elsimate in the name. The logic is OK but let down by lack of recovery and the dropping of a digit in twelve digit negative numbers. The best thing about it is the carry strap and bright display. |
| Components: | 1 x cpu: NEC uPD227C K45106, 28 pin DIL, 0.6" width,
black plastic 1 x 6 digit VFD display, single tube round faced, Futaba 6-CT-04 4E (May 1974) 2 x transistors 13 x diodes 12 x capacitors 4 x resistors 2 x resistor arrays 1 x transformer: 1197 |
| Boards: | Only one main board (N1176CC) that doubles as the keyboard board. It is attached to the front by five screws. |
| Construction: | Remove the screw from the rear and very gently lever the top sides apart, pushing in the rear section. Hinge off from the bottom and the back will come off. Quite difficult so be careful. |
| Logic comments: | The (CE) key clears the last number entered whilst (C) clears the whole calculator |
| Input overflow is suppressed, inputting a thirteenth digit is ignored | |
| If you input more than six digits the red LED comes on and the display switches automatically to the least significant six digits | |
| The red LED does not light to indicate an overflow above six digits - you have to know it does! | |
| There is automatic constant on all four functions | |
| Negative numbers are shown by a "-" displayed in the far left (first) digit thereby allowing only eleven digit negative numbers to be displayed. If a result is a negative twelve digit number, you lose the display of the least significant digit but it is still there in the register | |
| Divide by zero result in the display of "000000" and is not recoverable | |
| Overflow results in the display of "000000" and is not recoverable | |
| The (<->) key toggles the display between the most and least significant six digits with a red LED indicating you are displaying the least significant ones. | |
| No bugs found |
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The image on the
left is of the
interior and shows the single double-sided cpu/keyboard board from
the rear. Quite a few components which is to be expected at such an early
date.
Most of the components on the right are for generating the high voltages needed for the display tube. Compare this to the inside of the EL-8002. |
