Texet Pocket-8M

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Calculators: Handheld: Texet Pocket-8M

		Size (approx):	78mm x 140mm x 23mm (max) (w x h x d) Weight 118g excluding batteries (manual states 120g)
		Power:	3.0V DC using 2 x AA size batteries. It accepts an adapter (3V DC, 0.36W) through a socket on the left side to the top.
		Case:	Two piece matt white plastic case with rounded, but not symmetrical, top and bottom. The front is dominated by a gold coloured brushed aluminium panel which is inset, follows the contours and printed with black text for the switch labels. Through this protrudes a display escutcheon in white plastic with a ridged design and raised lettering painted gold with the brand and model number. An angled green plastic display filter sits flush in its surround. The Casio-like keys are medium travel with a soft click and the switches are a bit like 1970s Hi-Fi equipment.
		Display:	8 digit green VFD with a ninth digit for negative and error indication.
		Features:	Standard four functions with percentages, change sign and two-function switched memory. Floating/fixed decimal and financial input modes.
		Age:	1975
		Manufacturer:	Texet, Douglas, Isle of Man, made in Japan, serial number 8508494.
		Comments:	Not often seen Texet model with a design that reminds me of the Casio pocket range with the ridged plastic area. Stunning white and gold colour scheme is innovative for its day that was also available in black and gold. The logic is poor with negative zero bugs, archaic percentage function and too simple memory with the Texet confusing change sign key. The original case is soft black plastic with open top and Texet printed in silver. The gold colouring tends to wear off around the power switch.

Components:	1 x cpu: Mitsubishi M58618 541E, 28 pin DIL 0.6" width black plastic 1 x 9 digit VFD unit: single glass tube flat face: Futaba 9-ST-10 5J (September 1975) 2 x transistor 12 x diodes 6 x resistors 2 x resistor arrays 6 x capacitors 1 x transformer module: F5
Boards:	The main cpu board (800502) sits face down and lose above the keyboard assembly (KB-512958) which are joined by 14 short strong wires. The keyboard is attached to the front with nine screws.
Construction:	Remove the small screw inside the battery compartment. Held together by internal lugs which can be difficult to open without damaging. If you must try then I found the easiest way was to lever apart the top edge and then travel down the sides. Eventually the back lifts away, hinging to the right.

Logic comments:	The (CE) key is used to clear the last entry whilst (C) clears the whole calculator.
	Input overflow is suppressed, keying in a ninth digit is ignored
	There is automatic constant on all four functions
	Negative numbers are indicated by a “-“ in the far left (ninth) digit thereby allowing full eight digit negative numbers.
	Overflow shows the result and “C” (“E” if negative) in the far left (ninth) digit and is recoverable using (C)
	Divide by zero results in zero and “C” in the far left (ninth) digit and is recoverable using (C)
	The percentage key in isolation, just divides by 100 and if used repeatedly ends with "0.0000000"
	Memory store is indicated by the decimal point of the far left (ninth) digit
	The memory can only be used in accumulation mode: switching the memory on causes all results of the (=) key to be added to memory
	Memory overflow is flagged, recoverable using (C) and retains the result shifted
	The change sign function (CS) can be used in mid number entry and before
	A switch selects between [F] floating decimal, [2] fixed two digit decimal and [A] financial input. The latter causes (2)(3)(4) to register as "2.34"
	It suffers the negative zero bug: key in (1)(-)(2)(=) to give "-1" now (+)(1)(=) will give "-0"
	It suffers the divide to negative zero bug (once): key in (1)(CS)(/)(1)(0)(=)(=)(=) etc until you get "-0"

Manual

This image shows the manual which measures 128mm by 80mm and is eight printed pages in total. The cover is green and black whilst the other pages are black only.

In English only there are simple instructions and examples.

Texet, Douglas, Isle of Man, printed in Japan.