Canon F-71

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Calculators: Handheld: Canon F-71 (Scientific/Statistical Calculator) (Palmtronic)

		Size (approx):	83mm x 150mm x 26mm (w,h,d) Weight 182g excluding batteries
		Power:	6.0V DC, 4 x AA size batteries. Also accepts adapter/charger (AD-1 6V 0.6W, very odd connector) through a socket on the top side to the far left. The rear notice says that the Canon Ni-Cd Battery Pack 2 can be used. The on/off switch is on the right hand side.
		Case:	The main case is a two-piece, patterned black plastic construction which is thicker than most Canon calculators of its time. A neutral display filter is flat and slightly raised, given a bright image. There is a raised black plastic display escutcheon with a silver painted line. The front is dominated by a wrap around brushed aluminium panel. It is printed black, gold, white and green for various labels. They keys are soft with a gentle click and work very well. A black printed metallic label sits on the lower edge in its own recess with the text "Canon Palmtronic".
		Display:	12 digit green VFD with a thirteenth for error and negative indicators and a fourteenth for negative exponent indication.
		Features:	4 function calculator with change sign, square root, squares, powers, reciprocal, factorial, polar-rectangular conversion, pi, DMS, trigonometric and transcendental functions, extensive statistical functions., DRG switch (on the top edge). Three function, five store memory.
		Age:	1977
		Manufacturer:	Canon Inc., Japan, with a serial number sticker on the battery compartment door: 673209
		Comments:	Fabulously sophisticated Sci/Stat calculator that was built to last - and it has. Loads of memories, loads of digits, switches everywhere - what more could you ask? Without a manual, some of the higher functions are difficult to decipher and the colour scheme is a mess - but who cares? The logic appears reasonable with no major bugs, but the lack of error recovery is annoying. This range from Canon was superseded by their first LCD calculators, such as the Canon F-72 a few years later and a departure from the normal Texas chips used.

Components:	1x cpu: Hitachi HD36140 7D35 (April 1977) 42 pin DIL, 0.6" width black plastic 1 X IC: Hitachi HD36141 7D13, 16 pin DIL, 0.6" width black plastic 1 x 14 digit VFD: single tube flat front face 2 x transistors 6 x diodes (2 on the keyboard assembly) 4 x capacitors 4 x resistors 1 x resistor array 1 x transformer
Boards:	The main cpu board floats free, attached to the keyboard assembly which is fixed to the front with plastic lugs. The two are joined by 20 strong copper wires.
Construction:	Remove the screw from within the battery compartment. The pop the side lugs carefully by pushing in the rear section of the case. Travel around the case. Watch out as the on/off switch label and top switch extender will fall out easily.

Logic comments:	The (CI) button is used to clear last entry of a number and (C) to clear the whole calculator
	Overflow on number input is suppressed; typing in an eleventh digit is ignored
	An overflow error displays just "E0." in the far left two digits and is not recoverable
	Divide by zero displays just "E0." in the far left two digits and is not recoverable
	There is automatic constant on multiply and divide only
	Negative numbers are flagged by a "-" sign in the far left (fourteenth) digit thereby allowing full ten digit negative numbers
	Full scientific mode display is 10+2 digits after using the (EXP) key to enter the exponent
	The change sign function (SC) can be used in mid number entry
	Square roots of negative numbers are not allowed; the result displays just "E0." in the far left two digits and is not recoverable
	Memory store to one of five locations: to store in memory three use (Mn+)(3), to recall from three use (RMn)(3) and cancel is (CMn)(3)
	There is no indication of memory store - you have to remember it
	Higher functions are accessed by using the (INV) key first - and the decimal point of the first digit lights to remind you
	The (Off/n/n-1) switch and the (DLT), (OUT)(SUM) keys are used in statistical mode. Maybe the (X/XY/LR) is too.
	There is a gradian, degree, radian switch on the top edge

	Rather than add secondary key labels, canon decided to leave you a handy guide on the back to the statistical functions. This shows that there are actually 14 different storage registers in this mode, even though only five are enabled as memories in the standard mode.