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Calculators: Handheld: Imperial 1020
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Size (approx): |
73mm
x 120mm x 23mm (w,h,d) |
| Power: | 3V DC, 2 x AA size batteries. It accepts an adapter (undefined) through a socket on the bottom side to the far right. The on/off switch is three-position for Charge/Off/On. | ||
| Case: | Compact two-piece case made from black matt plastic. The front has a full size wrap over brushed aluminium panel. A small black-printed metallic sticker sits in its own recess and has the company name. An inset and tilted green plastic 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, error and memory indication. | ||
| Features: | Standard four functions and percentages, change sign, square root, pi, squares, reciprocal and four-function memory | ||
| Age: | 1977 | ||
| Manufacturer: | Imperial, made in Japan, serial number 69959401 | ||
| Comments: | Compact blocky calculator with a quality feel to it. The logic is quite good and only let down by partial recovery. The original case is black plastic with stiffened sides and collapsible edging. It is open topped with large square side cut-outs. Very similar to Triumph/Adler models. |
| Components: | 1 x cpu: Sharp LI2013 7D2 013
(April 1977 date code), 28 pin DIL, 0.6" width black plastic 1 x 9 digit VFD unit flat face single tube display with black plastic tape shroud 1 x transistor 5 x diodes 7 x capacitors 4 x resistors 1 x transformer: TC-4A |
| Boards: | The keyboard assembly (GK400 M213) (GICO 52.6.23 - which is date code 23rd June 1977) sits on top of the battery compartment and main CPU board (M-1020 EBANA 006-0) and is joined by a 16-eay clear ribbon cable. The the whole assembly floats free and can by hinged out to the left of the case. |
| Construction: | Held together by internal lugs only. Loosen the power socket fixing ring and remove the rectangular rubber bung in the battery compartment, You will then see an exposed lug on the button edge that you can pop. Travel around the edges pushing in the rear section. The front will eventually lift 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. |
| Input overflow is suppressed, keying in a ninth digit is ignored | |
| There is automatic constant on multiply and divide only | |
| Overflow shows the result with "C" (“E” if negative) in the far left (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 | |
| Negative square root are not allowed and show zero with "C" in the far left (ninth) digit and is not recoverable | |
| The change sign (-) function can be used in mid number entry but not before | |
| Memory store is indicated by the decimal point of the far left (ninth) digit | |
| Memory clear is performed by pressing (Mout) twice | |
| Memory overflow flags the error and retains the original number | |
| No bugs found |
