Decimo Super Vatman (type II)

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Calculators: Handheld: Decimo Super Vatman (type II)


		Size (approx):	83mm (max) x 132mm x 30mm (max) (w,h,d) Weight 144g excluding batteries
		Power:	6.0V DC, 4 x AA size batteries, 0.3W. Also accepts adapter/charger (undefined) through a top side socket on the right. The on/off switch is in the middle of the top side and is a three position switch for On/Off/Charge. A note on the back sticker reminds you to only use the charge position with rechargeable batteries in place.
		Case:	Chunky two piece matt plastic case where the bottom is light grey and the top black. Oversized, wrap over green display filter has a white printed model name. It has frosted edges around the display and gives a very clean bright image. A black printed metallic sticker with the brand name sits in its own recess. The keyboard surround is brushed aluminium. Top is slightly tilted upwards, including the back which causes the calculator to rock, especially with no batteries to weigh it down. Keys are squishy but positive to use.
		Display:	8 digit green VFD display with an extra symbol cluster on the far right for negative, memory and error indicators.
		Features:	Basic four function with percentages, change sign, squares, reciprocal, register exchange, square roots. and four-function memory.
		Age:	1975
		Manufacturer:	Decimo Electronic Handy Calculator. Made in Japan. Serial No. 509 08453
		Comments:	Classic calculator which has a quality feel in the hand. Logic sound. Imbalance on the desk let it down. For those non-UK viewers, VAT stands for Value Added Tax - the purchase tax system in the UK.

Components:	1 x cpu; Rockwell A4641PA 7526 (week 26 of 1975) 42 pin Staggered DIL, 0.6" width 1 x 8 digit plus symbol cluster VFD; single round faced tube 2 x transistors 7 x diodes 6 x capacitors 7 x resistors 2 x resistor arrays 1 x transformer
Boards:	The keyboard assembly sits on top of the battery compartment and is attached to the main cpu board below with a 12-way ribbon block.
Construction:	Front can be gently prized off after using the coin guide at the top. Squeeze the cream plastic sides so the lugs separate without breaking.

Logic comments:	The Clear key (C) is used once to clear an input number, and a second time to completely reset the calculator
	Overflow on the input of a number is suppressed - typing in nine digits ignores the ninth
	The constant function is automatic on multiply and divide only
	The negative sign is shown by a "-" in the far right symbol cluster thereby allowing full eight digit negative numbers.
	Memory store is flagged by a "M" in the lower part of the far right symbol cluster
	A divide by zero error is shown by a "°" and "-" in the far right symbol cluster and is recoverable using (C)
	Overflow shows the result and a "°" and "-" in the far right symbol cluster and is recoverable using (C)
	Negative square roots are allowed and result in a negative answer
	The change sign function can be used in mid number entry
	To store in the memory key in (M)(+) or (M)(-), to recall use (M)(=) and to delete (M)(C)
	The Exchange key (EX) is used to invert the current display and last number entered,

	Here you can easily see the components crammed into the top of the case - the whole of the bottom being taken up by the keyboard assembly on top of the battery compartment. You can make out the symbol cluster on the right side of the VFD tube and the staggered pins of ICs common to Rockwell.