Corvus 415

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Calculators: Handheld: Corvus 415

		Size (approx):	76mm x 150mm x 36mm (max) (w,h,d) Weight 216g including rechargeable batteries, 134g without.
		Power:	6.0V DC using 4 x AA sized rechargeable battery pack. It accepts an adaptor (6V DC 100mA, centre negative Model A3310) through a socket on the top side in line with the (CM) key. Charging time is quoted as 12 hours and it states you should never operate it on batteries for periods longer than 12 hours or you will damage the batteries.
		Case:	Made from a two-piece matt beige coloured plastic case that has every edge rounded with gentle curves. The overall profile is slightly wedge shaped for desk use. The red plastic display filter is heavily inset and angled and gives a bright and wide angled image. Below the display is a thick brown and silver painted brand name plate which is proud as there is no recess for it. A brown leather-effect patterned plastic keyboard surround adds to the feel of quality. They keys are soft touch, very bouncy and work well on this example.
		Display:	8 digit red LED with a ninth digit for negative, memory and error indicators.
		Features:	Standard four functions with percentages, register exchange, reciprocal and four function memory.
		Age:	1974
		Manufacturer:	Corvus Corporation, Dallas Texas, serial number 415-0197222
		Comments:	Quality feeling calculator with a lovely LED display that works well as a handheld or desktop. The logic is very sound but lack of recovery is annoying. The original case is brown plastic with inner cotton liner. It has a side-top-side zipper which goes 2/3 the way down the sides.

Components:	1 x cpu: Mostek MK50203N 7425 (week 25 of 1974), 28 pin DIL, 0.6" width 1 x IC: ITT 508N 7430, 18 pin DIL, 0.3" width 1 x 9 digit red LED display unit 1135-0239 1 x transistor 0 x diodes 2 x capacitors 10 x resistors 1 x transformer Paktransformer AA 1013 1/7426
Boards:	The main board (Corvus 17001353B) floats in mid air as it was attached to two pillars and the rear screws. It is connected to the keyboard assembly via a 14-way ribbon cable. The keyboard is fixed to the front with three buckets of glue! The display board is held in by melted pillars of plastic.
Construction:	Remove the two screws from the rear and the two smaller ones underneath the battery pack. The back springs off easily.

Logic comments:	(C) cancels an incorrect numerical entry, whilst a second press clears the calculator
	Input overflow is suppressed, typing in ninth digits ignores the ninth
	There is automatic constant on multiply and divide only
	Negative numbers are shown by a minus in the immediate left digit travelling into the far left (ninth) digit thereby allowing full eight digit negative numbers.
	Divide by zero results in zero and an upper "n" in the far left (ninth) digit and is not recoverable
	Overflow shows result with upper "n" (or upper "0" if negative) in the far left (ninth) digit and is not recoverable
	It is possible to hook up the calculator by storing an error; try entering 99,999,999 (M+)(M+) which can not be recovered using (C), only (CM)
	Memory store is indicated by a lower "L" in the far left (ninth) digit
	The percentage key just divides the number by 100 on the first press only
	(EX) is used to exchange the registers; i.e. to invert a division calculation

	This over-sized box measures 112mm by 266mm and is 67mm deep. It is large enough to accommodate the adapter that was included. Printed in brown, caramel and orange it is a two-piece lid and base construction. There is no country of origin - or in fact any other information except the model number on the sides.		The manual measures 89mm by140mm and is 26 printed pages. The cover looks like three process colours whilst the inside is black and white. Plenty of examples and instructions in English only. The back page has an attached, perforated Return Warranty Card. Corvus Corporation, Dallas, Texas, Printed in USA 1001433. The service centre address was 13030 Branchview Lane, Dallas, Texas 75234.