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Calculators: Handheld: Galfa 81/3

Size (approx): 75mm x 155mm x 25mm (w,h,d)
Weight 138g excluding batteries.
Power: 4.5V DC, 3 x AA size batteries the far left battery slot is a dummy.  Also accepts adaptor/charger (undefined though centre positive) through a top side socket on the left.  
Case: Brick-shaped calculator with brown matt plastic base and black neutral coloured top dominated by smooth cream plastic keyboard surround.  Logo on the front is painted white (not raised like most Rockwells) and the two side rails are painted silver.  Small neutral display filter shows the digits clearly. Squashy keys are very positive to use and brown orange colour scheme quite pleasant.  There is a handy reminder sticker (black printed metallic) on the back with example calculations.  There is no model number printed on the front panel as one would expect.
Display: 8 digit blue VFD display with a ninth digit for negative and memory indicators.
Features: Four function with square roots, change sign, percentages and four-function memory.
Age: 1976
Manufacturer: Made for Galeries Lafayette by Rockwell International.  Rockwell International, Microelectronic Product Division, Anaheim, CA 92803. Made in Japan.  Serial number 111000.086.
Comments: Lovely typical Rockwell calculator with sound logic only let down by the negative square roots.  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 soft plastic with flip top cover and tuck-in tab at the front.  This is obviously a branded Rockwell 24RD-II.

Components: 1 x cpu: A5901CA 4-7620 (week 20 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 smoothing choke
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: The Clear key (CE/C) is used once to clear an input number a second time to completely reset the calculator
Overflow on the input of a number is suppressed, keyin a ninth digit is ignored
The change sign function can be used in before, during or after number entry
The constant function is automatic on all four functions
Negative numbers are flagged by a "-" sign in the far left (ninth) digit thereby allowing full eight digit negative numbers.
Negative square roots are allowed and result in a negative answer
A divide by zero shows "0.0.0.0.0.0.0.0" and is recoverable using (CE/C)
Overflow shows the result with all decimal points alight and is recoverable by using (CE)
Memory storage is flagged by the ninth (far left) digit decimal point alight
Overflow in memory is flagged an retains the original number
It suffers the pseudo fixed decimal bug: key (1)(+)(.)(0)(0)(0)(=) to get "1.000" which remains a fixed three digit decimal until more digits are needed or you use multiply or divide