Continental

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Calculators: Handheld: Continental


		Size (approx):	57mm x 112mm x 16-18mm (w,h,d) Weight 66g excluding batteries
		Power:	3V DC using 2 x AA batteries which appear to be slightly too big for the compartment. It accepts an adapter/charger (undefined) through a socket on the top side to the far right. The on/off switch is on the left hand side in line with the display. There is a power down function after about 20 seconds to conserve battery power. There is a red ribbon pull in the battery compartment to help battery removal.
		Case:	Very compact brick shaped calculator that is slightly raised at the display/battery compartment area. It is made from a two-piece smooth beige plastic case. The red plastic display filter sits flat and flush and gives a very nice wide angle image. Below the display sits a black and red printed metallic sticker with the brand. The keys are short travel with a positive click but rattle when shaken.
		Display:	8 digit red LED with flat digits and a ninth digit for negative, power down, and error indicators
		Features:	Standard four functions with percentages and restore display function
		Age:	1974
		Manufacturer:	No manufacturing details of any kind
		Comments:	Very compact and neat calculator that reminds me of the Prinztronic Mini series. I have seen one other calculator that looks exactly the same as this one on the web with a Hanimex label, but again no model number. I acquired this one from Canada, so it may have been a one-off in that area only. Quality is good, display is one of the best, but the case is a shade too small for the batteries. The logic is OK with only the pseudo fixed decimal bug letting it down. The original case is square-shaped soft black plastic with open top. This calculator is surprisingly early for its compactness. Reminiscent of some Prinztronic models but very similar to the Hanimex VP8.

Components:	1 x cpu; Texas TMS0803NC 7415-1 (week 15 of 1974), 28 pin DIL, 0.6" width 1 x 9 digit red LED unit: Bowmar Optostic M2 5174 11 x transistors 4 x diodes 6 x capacitors 11 x resistors 1 x transformer; CT-860 TDK
Boards:	The whole inside assembly sits loose. The main cpu board is attached to the keyboard assembly by a 13-way connector.
Construction:	Six internal lugs hold the whole case together. The best way to open it, I found, was to use a fingernail to prize away the front of the case. Very difficult so if in doubt do not attempt as damage may result.

Logic comments:	(CE) clears the last entry whilst (C) clears the whole calculator
	Input overflow is suppressed, inputting a ninth digit is ignored
	There is automatic constant on all four functions
	Negative numbers are shown by a minus sign in the immediate left hand digit, travelling into the far left (ninth) digit thereby allowing full eight digit negative numbers
	Divide by zero shows zero and "C" in the far left (ninth) digit and is recoverable using (CE) or (C)
	Overflow shows the result and "C" (or "E" if negative) in the far left ((ninth) digit and is recoverable using (CE) or (C)
	The display will switch off after about 20 seconds to conserve power - with just the upper horizontal segment of the far left (ninth) digit alight. Using the restore key (R) to recover.
	It suffers the pseudo fixed decimal bug; try (0)(.)(0)(0)(0)(+)(1)(=) will give you "1.000" which will stay as a fixed three digit decimal number until you use multiply or divide.

	This scan shows the inside assembly of the calculator. Note the large number of transistors to drive the display - a sign of an early 1970s pocket calculator. This really is an ingenious cram! the whole board is not much bigger than the Texas IC. Notice also the spare holes suggesting that this board was to be used for several different models. Compare this with the Hanimex VP8 inside.