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Calculators: Handheld: Imperial 90K
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Size (approx): |
73mm
x 120mm x 20mm(max) (w,h,d) |
| Power: | 6V DC, 4 x AAA size batteries. It accepts an adapter (undefined) through a socket on the bottom side on the far right. | ||
| Case: | Square, compact two-piece case made from black smooth plastic. The front has a full size wrap over aluminium panel. A small black-printed metal plate sits in its own recess and has the company name and model number. Small tilted green display filter gives a bright display. Squishy, medium travel keys work well enough with a subtle colour scheme. | ||
| Display: | 8 digit green VFD, with a ninth digit for negative and error indication. | ||
| Features: | Standard four functions and percentages | ||
| Age: | 1975 | ||
| Manufacturer: | Imperial Typewriter and Business Machines Ltd, Leicester, England. Serial No. 90K 014974, made in Japan | ||
| Comments: | Nice compact but basic calculator solidly built with sound (if antiquated) logic. From a British company more famous for its typewriters. It is likely that this calculator is a branded Adler/Triumph. Original case is black plastic with a stiff front and rear, two side cut-outs and collapsible sides. Identical inside to the Adler 80C. |
| Components: | 1 x cpu: NEC µPD943C H55236 1 x 9 digit VFD flat face single tube display 2 x transistor 7 x diodes 7 x capacitors 0 x resistor arrays 9 x resistors 1 x transformer: DCT-05 |
| Boards: | The keyboard assembly sits on top of the main CPU board (ref 80S-C) and is joined by 13 strong wires. The the whole unit floats free. |
| Construction: | Gently squeeze in the rear section side panels and prize apart, the front then lifts off. Very easy to damage so if you are not sure then don't do it. |
| Logic comments: | (CL) is used once to cancel the last number entered and (C) to clear the whole calculator. |
| There is automatic constant on multiply and divide only | |
| The addition and subtraction is in Reverse Polish Notation (RPN): i.e. 9-4 is entered as (9)(+)(4)(-) and 5+6 is entered as (5)(+)(6)(+). | |
| Input overflow is not suppressed, inputting a ninth digit is results in an overflow and is recoverable using (CL) | |
| Overflow shows the result with "C" (“E” if negative) in the left most (ninth) digit and is recoverable using (CL) | |
| Divide by zero shows "C” in the far left (ninth) digit and is not recoverable | |
| Negative numbers are shown with a "-" in the far left (ninth) digit allowing eight-digit negative numbers | |
| No bugs found |
