Sharp Elsimate EL-1112

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Calculators: Handheld: Sharp EL-1112 (Elsimate)

		Size (approx):	79mm x 137mm x 23mm (w,h,d) Weight 158g excluding batteries.
		Power:	3V DC, 2 x AA size batteries and recommends rechargeable batteries EA-18B, 2.4V. It accepts an adapter/charger (EA-17E, 3V 0.35W) through a top side socket on the far right.
		Case:	Modern slim line two-piece plastic case in smooth black and beige. The front is dominated by a wrap around brushed aluminium panel. This is printed black for the brand, model number, switch labels and key surround. A flat and slightly proud oversized green plastic display filter gives a good bright image. They keys are soft and bouncy with a soft click but work well.
		Display:	10 digit green VFD with an eleventh digit for negative and error indicators and upper commas for thousands indication.
		Features:	Four function with percentages, square roots, change sign, total count, powers, mark-up, register exchange and five-function memory. Switched floating and fixed decimal modes with accounting input.
		Age:	1980
		Manufacturer:	Sharp Corporation, made in Japan, serial number 03000465 on a sticker in the battery compartment.
		Comments:	Stylish slim with a high quality solid feel. Quirky right hand extra digit is typical of Sharp and the unusual side switches a nice feature. Colour coding for the keys is simple with blue for memory and grey for higher functions – in a set of small keys like the Casio FX series. The logic has a few problems, suffering from a lack of consistent recovery, strange operation of accounting mode and limited power function. The original cover is soft black plastic, open top and half-moon cut-outs on the sides with Sharp embossed on the front and Made in Japan on the back.

Components:	1 x cpu: Sharp LI2042 0B2 005 (date code 2 (week or day) February 1980), 28 pin DIL , 0.6"width black plastic 1 x 11 digit VFD unit flat faced single tube: Futaba 11-ST-64 0B (February 1980) 1 x transistor 6 x diodes 3 x resistors 4 x capacitors 1 x transformer: TDK 1459 Japan
Boards:	The main cpu board (F1511A) sits on top of the keyboard assembly and secured by one screw. They are joined by a 18-way ribbon cable. The keyboard is attached to the front with a two screws and plastic lugs. The rear section of the case has a metal screening plate which electrically connects to the main board.
Construction:	Remove the screw in the battery compartment. Not much use as it is held together with internal plastic lugs. Whilst there is a lug accessible to the left of the battery compartment, I found it best to prize the front section out on this side first. Eventually, and carefully, the rear section will come away.

Logic comments:	The (CE) key is used to cancel an entry and (C) clears the whole calculator
	Overflow on the input of a number is not suppressed, keying in an eleventh digit causes an overflow, which is not recoverable
	There is automatic constant on all four functions
	Change sign (+/-) can be used in mid number entry but not before
	Negative numbers are flagged by a "-" sign in the far right (eleventh) digit thereby allowing full ten digit negative numbers.
	Overflow shows the result with "C" ("E" if negative) in the far right (eleventh) digit and is recoverable using (CE)
	A divide by zero shows zero and "C" in the far right (eleventh) digit and is not recoverable
	Memory store is indicated by the decimal point of the far right (eleventh) digit
	The key (X <> M) is used to exchange the memory contents with the current register
	Overflow in memory retains the original number
	The key with an up/down arrow is a register exchange
	The (CT) key returns the total number of times (=) has been pressed
	The power key (aⁿ) can only raise powers with positive integers
	Negative square roots are not allowed and result in zero and overflow which is not recoverable
	The (MU▲%) key can be used to mark up: to add 10% to 50 key in (5)(0)(X)(1)(0)(MU) to give “55”
	You can switch between floating mode [F] or fixed 3/2/0 digit decimal modes
	The [A] options allows inputting accounting format so that keying in (4)(9)(9) result in the input of “4.99” but rather disconcertingly it does not show this on input like most calculators
	No other bugs found

This image shows the main board attached to the keyboard assembly (to the right). For such a late VFD date of 1980, there are still lots of components, mostly to drive the high voltages of the display.

The holes that you see are for the screw and several locating plastic pillars. Notice also the typical Sharp ribbon cable to the right - wafer thin plastic cable clamped by metal brackets which doubles as the key connections.