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Calculators: Handheld: Rockwell 14RD

Size (approx): 75mm (max) x 155mm x 25mm (max)  (w,h,d)
Weight 150g excluding batteries


6.0V DC, 4xAA size batteries.    Also accepts adaptor (undefined though 3V centre positive worked fine) through top end socket on the left. 
Case: Sturdy stippled brown plastic case with cream keyboard surround printed with brown text and line.  A neutral plastic display filter sits slightly inset to the edges of the case and allows 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 no ninth digit.  The minus indicator is a red LED on the top right corner.
Features: Four function plus percentages. 
Age: 1975
Manufacturer: Rockwell International, Microelectronic Product Division, Anaheim CA 92803.   Serial No. 110562.046.  I also have another with serial No, 116436.026, made in Japan.


Lovely typical Rockwell calculator with reasonable 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.  The red LED on mine has a habit of glowing after switch off for about 1/2 a second.

Components: 1 x cpu: A5911CA 7541 (week 41 of 1975) 42 pin DIL 
1 x single glass tube, flat faced 8 digit VFD display plugs into socket
2 x transistors
5 x diodes
7 x resistors
6 x capacitors
1 x smoothing choke
2 x SIL resistor arrays
1 x 3mm red LED 
Boards: Keyboard board  is attached to front by 12 screws and hinges to the main board on 14 stiff copper wires.  Main CPU board  is clip-fixed to the base.  The main board has space for an extra transistor and LED - perhaps and overflow indicator.
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: (CE/C) cancels an incorrect numerical entry, pressing a second time (C) clears the calculator
Input overflow is suppressed, keying a ninth digit is ignored
Negative numbers are indicated by a pin-point red LED thereby allowing full eight digit negative numbers
Overflow displays the shifted number with all decimal points lit and is recoverable by using (CE/C)
Divide by zero shows "" and and is recoverable by using (CE/C)
It has automatic constant on all functions
It suffers the pseudo fixed decimal bug: key in (1)(+)(.)(0)(0)(0)(=) to get "1.000" which remains a fixed three digit decimal until you need more digits or use multiply or divide