Rockwell 14RD-II

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Calculators: Handheld: Rockwell 14RD-II

		Size (approx):	75mm (max) x 155mm x 25mm (max) (w,h,d) Weight 134g excluding batteries
		Power:	4.5V DC, 3xAA size batteries. The battery compartment has a pin in one of the four battery sockets in order to stop insertion. Also accepts adapter (undefined) through top end socket on the left.
		Case:	Sturdy stippled brown plastic case with light beige keyboard surround. Neutral display cover shows a clear view of the numbers. Squashy but positive keys work well. The raised Rockwell logo and two vertical edges are painted silver.
		Display:	8 digit blue/green VFD with a ninth on the far left to show the minus sign.
		Features:	Four function plus percentages.
		Age:	1976
		Manufacturer:	Rockwell International, Microelectronic Product Division, Anaheim CA 92803. Serial No. 107582.096
		Comments:	Lovely typical Rockwell calculator with sound logic and clear display. Both the silver trim and any lettering on the keyboard surround have a tendency to rub off so finding good examples is not easy. Built to last - and they have. Original case is black plastic with flip top cover and tuck-in tab at the front. Rockwell made a branded version of this calculator called the House of Fraser 14HF.

Components:	1 x cpu: A5901CA 7621 (week 21 of 1976) 42 pin DIL 1 x single glass tube, flat faced 9 digit VFD display 2 x transistors 4 x diodes 7 x resistors 6 x capacitors 1 x transformer
Boards:	Keyboard board (GK300-1) is attached to front by 12 screws and hinges to the main board on 14 stiff copper wires. Main CPU board (R-14a-5901S) is clip-fixed to the base.
Construction:	Remove the two small screws in the battery compartment. Gently push out the front keyboard which hinges up from the display surround. Pop off the display surround by using gently pushing a blunt object through the three slots on the rear.

Logic comments:	There is automatic constant on all four functions
	Input overflow is suppressed, inputting a ninth digit is ignored
	Negative sign is shown in the far left (ninth) digit thereby allowing full eight digit negative numbers
	Divide by zero shows "0.0.0.0.0.0.0.0." which is recoverable using (CE/C)
	Overflow is shown by the result and all decimal points alight and it is recoverable using (CE/C)
	There is a trailing zero bug; try (1)(-)(0.00000) the answer is "1.00000" which remains until you multiply or divide. This is actually quite useful as an unofficial fixed decimal point system.