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Calculators: Handheld: First

		Size (approx):	78mm (max) x 127mm x 21mm (max) (w,h,d) Weight 114g excluding batteries.
		Power:	3.0V DC, 2 x AA size batteries, 0.2W. Also accepts adapter (3V 0.1A, centre positive) through a bottom-side socket on the right.
		Case:	Fabulous thick plastic two piece case. Rear section in smooth dark brown and the front in smooth orange. with brushed aluminium keyboard surround. A black printed metallic label sits in its own recess stating the brand name. The green plastic display filter is slightly inset and flat. Inset just a little further is the aluminium keyboard surround printed with black text for the additional functions. The keys are medium-travel, quite springy with a metallic ticking sound.
		Display:	8 digit green VFD display with a ninth digit for negative, memory and error indication.
		Features:	Standard four function with percentages, square root, squares, reciprocal, change sign, pi and four function memory
		Age:	1976
		Manufacturer:	Made in Japan, serial number Z032357.
		Comments:	You can't help but like this calc. Typical brown and orange colour scheme from the 70s. Pity it clashes with the green screen. Solid feeling although squishy keys are not so reliable. Use of a (F) function key keeps the number of keys to a minimum. The logic is pretty sound and only let down by carrying on past overflow and negative square roots. The original case is glossy black plastic with open top and half-moon cut-outs front and back. It is a bit of a tight squeeze. Very Like the Office H.

Components:	1 x cpu: NEC µPD946C R63546, 28 pin 0.6" width black plastic 1 x 9 digit VFD unit, glass tube round faced; Itron DP95A4 1 x transistor 5 x diodes 7 x capacitors 8 x resistors 2 x resistor arrays 1 x transformer
Boards:	The keyboard assembly (2409, looks like a GICO) sits lose on top of the main cpu board (Z801) and is connected via a 15-way ribbon cable. The main board sits lose in the rear section of the case.
Construction:	There are three small lever slots on each side which can be used to prize away the front of the case, which then lifts off easily, hinging from the bottom.

Logic comments:	The Clear Entry key (CE) is used to clear an input number, the Clear (C) to completely reset the calculator
	Input overflow is not suppressed, keying in a ninth digit results in an error which is recoverable by dividing by 10 (or a multiple)
	The constant function is automatic for all four functions
	The negative sign is shown in the far left (ninth) digit thereby allowing full eight digit negative numbers
	Overflow shows the result and "C" (or "E" if negative) in the far left (ninth) digit. You can carry on calculating with the overflow symbol on, up to 16 digit numbers before it reverts to zero
	Divide by zero shows zero and "C" in the far left (ninth) digit and is not recoverable
	Negative square roots are allowed and result in a negative number
	Higher functions are reached by a two key sequence, to get pi key in (F)(+) but there is no indication of the "function mode" and (CE) can be used to cancel function
	Memory storage is indicated by a decimal point in the far left (ninth) digit
	Change sign can be used in mid number entry
	No bugs found

With the front removed and the keyboard swung back, the main cpu board is exposed. Having the adapter socket and the batteries at different ends means long flying cables have to span the case.

You can just see the ribbon cable at the bottom of the image which connects the keyboard.