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Calculators: Handheld: Ricoh Ricomac RC-8F

Size (approx): 83mm x 135mm x 26mm  (w,h,d)
Weight 152g excluding batteries

Power:

3V DC, 2 x AA size batteries.  It accepts an adapter (AD-8X, 0.24W) through a socket on the top side on the far right.
Case: Two-piece case in blue-grey and white smooth plastic. The raised keyboard surround is the same as the base. It has a eyelet on the top left for a carrying handle.  A slightly titled green filter give a clean bright display with a sculptured surround.  They keys are a lovely oval shape, soft but positive to use but the brown ones are a bit of an odd colour choice.  The company logo is moulded in its own recess whilst the model number is printed in blue.
.Display: 8 digit green VFD, with a ninth digit to display negative, error and memory indicators.
Features: 4 function calculator with percentages, change sign and three function memory.
Age: 1975
Manufacturer: Ricoh Company Ltd, made in Japan.  Serial No. (on battery cover) 7566-10 12377.  There is an additional recess on the back which in this example has a sticker labelled "Section" and "Name" to be filled in.  Normally I would have thought this to be a purchaser's company info, but it fits the recess perfectly.  Do you have one similar? 
Comments:

 

Solid enough calculator with lovely keys and bright display.  However, Input overflow and lack of error recovery let it down.  Original case is soft black plastic with flip over top and popper closing in the middle of the front.  Large capacitor on the power rails makes the calculator switch on and off gradually and just look at the resistor count!

Components: 1 x cpu: Toshiba T3315 5C, 28 pin DIL
2 x transistors
7 x diodes
7 x capacitors
0 x SIL resistor arrays
31 x resistors
1 x transformer: UT0907 5C04
Boards: The keyboard board (fixed using five screws) (ref. 5326-2111B) sits on top of the main board (75584 200A)and is joined by 16 stiff wires.  The whole assembly just sits in the case's four lugs and is prone to movement.
Construction: Remove the two screws in the battery compartment and the front easily hinges off from the bottom.

Logic comments: The (CE) button is used to clear last entry of a number and the (C) to clear the whole calculator.
Overflow on number input is not suppressed, typing in a nine digit number results in an overflow which is not recoverable
An overflow error is flagged with the answer displayed and "E" (whether positive or negative) in the far left (ninth) digit and is not recoverable
Divide by zero results in "E" being displayed with zero result in the far left (ninth) digit and is not recoverable
There is automatic constant on multiple and divide only
Memory store is flagged by the far left (ninth) decimal point and cancelled by double pressing the (MRC) key
Negative numbers are shown by a "-" in the far left (ninth) digit thereby allowing full eight digit negative numbers