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Calculators: Handheld: House of Fraser 44HF

Size (approx):

75mm (max) x 155mm x 25mm (max)  (w,h,d)
Weight 132g excluding batteries


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 an adaptor (undefined though I found 4.5V centre positive worked fine) 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 House of Fraser and two vertical edges are painted silver.   The keyboard surround has printed black lettering for the two switches, model number and three of the keys.
Display: 8 digit blue VFD with a ninth on the far left for negative indication
Features: Standard four functions with percentages, change sign, powers, brackets, square root, pi, squares, reciprocal, trig and log functions, scientific display and two function memory.  There is an extra switch for degrees and radians.
Age: 1976
Manufacturer: Made for the House of Fraser by Rockwell International, Microelectronic Product Division, Anaheim CA 92803.   Electronic Slide Rule Calculator. Serial No. 103245.066.


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.  This calculator is a branded version of the Rockwell 44RD.

Components: 1 x cpu: Rockwell A6500CA  42 pin staggered DIL
1 x 9 digit VFD flat panel glass faced display
2 x transistors
4 x diodes
6 x capacitors
2 x resistor arrays
7 x resistors
1 x transformer
Boards: The keyboard assembly is attached to the front of the calculator via 12 screws and to the cpu board  via 18 strong copper wires. 
Construction: Very gently poke a blunt pointed object through the two holes at the bottom of the rear side or the three at the top - whichever feels easier.  Squeeze apart the sides and this will pop out the keyboard surround.  Do the same through the top three holes for the display cover.

Logic comments: (CE/C) is used once to cancel the last number entered and a second time to clear the whole calculator.
Input overflow is suppressed, inputting a ninth digit is ignored
Negative numbers are shown with a minus  in the ninth (far left) digit thereby allowing full eight digit negative numbers
There is automatic constant on all four functions
Divide by zero shows a ""  and is not recoverable
Overflow shows a ""  and is not recoverable
Memory storage is not indicated - you have to remember it
Negative square roots are not allowed and result in an unrecoverable error
nth root of m is calculated by  (m)(Yx)(n)(1/x)(=)