Sharp Elsimate EL-8005S White

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Calculators: Handheld: Sharp Elsimate EL-8005S (blue and white)

		Size (approx):	85mm (max) x 137.5mm x 26mm (max) (w,h,d) Weight 144g excluding batteries
		Power:	6.0V DC, 4 x AA size batteries. Also accepts an adaptor (EA-14A) through top side socket on the right, 0.45W. Quoted battery life for manganese batteries is approx. 16 hours.
		Case:	Unusual two-piece plastic case in white smooth and blue 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 Korea. Serial number 5822745X 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 and it appears that some were made in Japan, others in Korea. The keyboard layout makes it look like there is a button missing. The logic is poor with no recovery, odd use of the right-most digit for symbols and the negative zero bugs.

Components:	1 x cpu: Hitachi HD36290 5J 31 (September 1975), 28 pin DIL 0.6" width black plastic 1 x 9 digit VFD; single tube round faced 1 x transistor 5 x diodes 8 x capacitors 7 x resistors 1 x resistor arrays 1 x transformer; TDK 1247 Japan
Boards:	The main cpu board (F1288C) is held in place by a screw and two plastic lugs above the keyboard assembly. The keyboard is attached to the front with one screw and to the main board with a 17-way ribbon cable. The back of the keyboard assembly forms the inside of the battery compartment. There is a large piece of black paper surrounding the display to cut out light and reflections,
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.

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 result and "C" (or "E" if negative) in the far right (first) digit 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"

The manual measures 130mm x 83mm and is 16 panel fold-out design. It is a three-colour (black, red and yellow) sheet with three pictures, one diagram and plenty of text for its size.

Printed in Japan it has some dubious translations and memorable quotes:

"Small, fast and easy. That's our new handy pocket size EL-8005S. Yet you can perform complicated calculations up to 8 digits."
"When the voltage of the battery is lowered, the display will become dark..."
"Take care not to mistake the battery polarity"
"...therefore, the decimal point of the displayed number means the unit of one hundred million."

This image shows the back removed. The main cpu board is fixed with a top centre screw (removed) and 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 uses an Hitachi IC rather than a Sharp IC - with no great saving on the number of components.