C.Itoh 8005

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Calculators: Handheld: C.Itoh 8005

		Size (approx):	85mm x 135mm x 25-32mm (w,h,d) Weight 136g excluding batteries
		Power:	6V DC using 4 x AA size batteries. It accepts an adapter (DC 6V 0.5W, 5.5mm plug centre negative) through a socket on the top side to the far right. A note on top specifies the adapter requirement.
		Case:	The case is two-piece glossy black plastic which sits equally well in the hand or on the desktop. The green plastic display filter sits flush with the case and is tilted at about 20 degrees. Just below this a small metallic sticker is printed black for the brand and model number and sits in its own recess. The keyboard surround has white text for the on/off switch label. The multi-coloured keys are soft and squishy but work well enough. The grey keys, however, suffer from too little contrast with the white labelling.
		Display:	8 digit green VFD with a ninth digit for negative and error indicators
		Features:	Standard four functions with percentages, square root, pi, and change sign
		Age:	1975
		Manufacturer:	CI Business Machines, a Division of C.ITOH & Co., Ltd., Tokyo. Made in Japan. Serial number F-11747.
		Comments:	Nice little calculator which is really only let down by the lack of overflow recovery. The original case is soft black plastic with a top flap that popper fastens to the front. Very similar to Decimo Vatman series.

Components:	1 x cpu; NEC µPD940C R5Z53M, 28 pin DIL, 0.6" width 1 x 9 digit VFD single unit flat faced 9-ST-10 5L (November 1975) 2 x transistors 4 x diodes 6 x capacitors 10 x resistors 2 x resistor array 1 x transformer: DCT-05 Zebra
Boards:	The keyboard assembly (8005-3 940C GK158-14 GICO Japan) sits loosely on top of the main cpu board (ref C80N-S10) which is held loose in the case.
Construction:	Quite tricky to open so be careful not to cause damage. You will see a small coin slot on the top edge which allows you to apply some pressure. I use a piece of wooden lollypop stick as is is soft. The lugs (two in the top and bottom edges, one on each side edge) will eventually pop when you push the rear of the case in.

Logic comments:	(CE) clears the last number entered whilst (C) clears the whole calculator
	Input overflow is not suppressed, inputting a ninth digit results in an error, which is recoverable using (CE)
	Negative numbers are shown with a minus to the immediate left of the number travelling into the far left (ninth) digit thereby allowing full eight digit negative numbers
	There is automatic constant on all four functions
	The change sign function can be used in mid number entry
	Divide by zero shows zero and “E” in the far left (ninth) digit and is not recoverable
	Overflow shows the result and “C” (“E” if negative) in the far left (ninth) digit and is not recoverable
	Negative square roots are allowed and result in a negative number

	The manual measures 130mm by 80mm and is eight pages. All internal pages are black only. It just has simple specifications and a few examples in English only. Printed in Japan. The incorrect "L" at the end of manual is real, not an artefact of the scan!
	This scan of the inside shows how similar the insides look to, say, a Decimo calculator of the same era. Keyboard assembly made by Gico. but the display is quite heavily tilted to suite the angle front.