Sharp Elsimate EL-8005 Cream

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Calculators: Handheld: Sharp Elsimate EL-8005 (cream and brown)

		Size (approx):	85mm (max) x 137.5mm x 26mm (max) (w,h,d) Weight 150g excluding batteries
		Power:	6.0V DC, 4 x AA size batteries. Also accepts an adaptor (EA-14A, 2.4W) through top side socket on the right, 0.45W.
		Case:	Unusual two-piece plastic case in cream smooth and brown matt plastic. The whole thing is shaped rather like a pint glass but fits in the hand quite comfortably. There is a very large green display filter that wraps over the top and gives a nice bright image. A metallic sticker printed black and red sits in its own recess in this filter. The keys are short travel and squishy but work rather well. They are labelled with engraved shapes painted black.
		Display:	8 digit green VFD with a ninth digit for negative and error indicators.
		Features:	Four function plus percentages.
		Age:	1975
		Manufacturer:	Sharp Corporation, Made in Japan. Serial number 52084603 on a sticker inside the battery compartment
		Comments:	Basic calculator that was obviously a design experiment, as no one copied it and its successor went back to normal. A red and black version was also available. I think this is cream rather than originally white as the inside of the case is the same colour. The keyboard layout makes it look like there is a button missing. The logic is not so good, with poor recovery and negative zero bugs.

Components:	1 x cpu: Hitachi HD3623 4L 31 (November 1974), 42 pin DIL 0.6" width black plastic 1 x 9 digit VFD; single tube flat faced: Futaba 9-ST-08A1 5C (date code March 1975) 1 x transistor 5 x diodes 8 x capacitors 3 x resistors 2 x resistor arrays 1 x transformer
Boards:	The main cpu board (PWBF1220CC) is held in place by two plastic lugs above the keyboard assembly. The keyboard is attached to the front with one screw and to the main board with a 14-way ribbon cable. The back of the keyboard assembly forms the inside of the battery compartment. There is a large metal plate on the rear section, insulated by a piece of acetate, that connects to the main board earth by a springy tab.
Construction:	Remove the screw from within the battery compartment and push out the lug that is clearly visible at the bottom of the compartment. This is more difficult than it sounds so be very careful not to damage your calculator. The whole back the lifts off, hinging from the top. The back is stamped inside with "50.1.8" which may be a date code (if so, the 8th January 1975).

Logic comments:	The (CE) key clears the last number entered whilst (C) clears the whole calculator
	Input overflow is suppressed, inputting a ninth digit is ignored
	There is automatic constant on multiply and divide only
	Negative numbers are shown by a "-" displayed in the far right (first) digit thereby allowing full eight digit negative numbers
	Divide by zero result in the display of ".......0.C." and is not recoverable
	Overflow results in the display of ".......0.C." (or ending in "E" if negative) and is not recoverable
	It suffers the negative zero bug: key in (1)(-)(2)(=) to give "-1" then (+)(1)(=) to give "-0"
	It also suffers the negative divide to zero bug: key in (1)(-)(=) to give "-1" then (/)(1)(0)(=)(=)(=) etc to eventually get "-0"

This image shows the back removed. The main cpu board is fixed with two lower plastic lugs. The keyboard assembly board below it also doubles as the battery connection system, the terminals being connected directly to it.

This particular version has a large soldered metal area to the bottom left of the main board that connects to a metal shielding panel on the rear of the case.