Silver-Reed 80

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Calculators: Handheld: Silver-Reed 80

	Size (approx):	75mm x 115mm x 18mm (max) (w,h,d) Weight 78g excluding batteries
	Power:	1.5V DC using 1 x AA size battery. It accepts an adapter (1.5V DC 0.1W) through a socket on the top side to the far left.
	Case:	Compact two piece case in smooth black plastic which is very slightly raised at the top. A full-width black printed metallic sticker sits in its own recess at the top with the brand and model number. A slightly tilted and flush neutral plastic filter gives a poor contrast display as it lets in too much light. There is a large brushed aluminium panel as a keyboard surround. They keys are very short travel and squishy but work OK.
	Display:	8 digit blue VFD with a ninth digit for negative and error indicators.
	Features:	Standard four functions with percentages, square root, reciprocal, squares, pi and change sign.
	Age:	estimated 1977
	Manufacturer:	Silver Reed, Silver Seiko International but no country of origin. Serial number 71138707.
	Comments:	Cheap but not too squeaky compact calculator let down by the low contrast display. The logic is a bit poor with no recovery, no cancel entry and input overflow. I would also expect a memory on a model with so many functions. The original case is soft black plastic with open top and half-moon side cut-outs. Similar to the Decimo Vatman Mini MII in case design and Similar Calculators.

Components:	1 x cpu: NEC D1801C R7101M, 22 pin DIL, 0.6" width 1 x 9 digit VFD; single glass tube with round front face 2 x transistors 4 x diodes 5 x capacitors 2 x resistors 1 X transformer
Boards:	The main board (51202) sits on top of the keyboard assembly which is attached to the front with 8 screws. A 15-way ribbon cable joins them together. The transformer sits in its own cut-out to keep the board as slim as possible.
Construction:	Remove the single screw from the back and gently prize off the front starting at the bottom. There are two lugs either side. Eventually you will be able to hinge around the top area and remove the back.

Logic comments:	(C) clears the whole calculator as there is no cancel entry function.
	Input overflow is not suppressed, inputting a ninth digit causes an overflow that is not recoverable
	Negative numbers are shown with a minus in the immediate left hand digit which travels into the far left (ninth) digit thereby allowing full eight digit negative numbers.
	The change sign function can be used in mid number entry
	There is automatic constant on all four functions
	Divide by zero shows "0” and “C” in the far left (ninth) digit and is not recoverable
	Overflow shows the result and “C” (or “E” if negative) in the far left (ninth) digit and is not recoverable
	Negative square roots are allowed and result in a negative answer

box

The box measures 80mm by 126mm and is 28mm deep. It is therefore just big enough to hold the calculator. Printed in blue only, it is a simple top and bottom tuck end construction. There is no information of origin on the box.