Olympia CD 71

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Calculators: Handheld: Olympia CD71


		Size (approx):	83mm x 150mm x 30mm (w,h,d) Weight 332g including batteries
		Power:	6V DC with internal sealed rechargeable batteries. It takes an adapter/charger (10V DC, 1.5W, centre negative) through socket on the right side at the far bottom.
		Case:	Sturdy brick-shaped three-piece case of matt black and silver coloured plastic. At the top of the right hand side is a metal tag for attaching a carry strap. The top is dominated by a wrap-around, flat and flush, neutral plastic display filter. Just below this, the silver plastic is printed in red and black for the brand logo. The keys are a medium travel squashy feel but appears to work well enough. Two of the switches are labelled with embossed lettering that may have originally been painted (?). The rear has a large metallic sticker with calculation reminders.
		Display:	8 digit blue VFD with odd upper left hand commas. There is an additional pin-point red LED to the lower left of the display for negative indication.
		Features:	Standard four functions, percentages and two function memory, switched memory. Additional switch for floating, 2 or 4 fixed decimal places. RPN logic.
		Age:	1974
		Manufacturer:	Olympia Werke AG, Wilheimshaven, Western Germany, made in Japan. Serial number 0305344.
		Comments:	Quite a nice heavy solid calculator with a plain design. The original case is soft black plastic with a top flap which tucks into a front band. This band is embossed with the word “Olympia. There is a slight cut out on the left hand side so that the carry strap can feed through. The logic is not bad with good recovery but let down by the archaic RPN and pseudo fixed decimal bug.

Components:	1 x cpu; Rockwell A1030PE 7410 (date code week 10 1974), 42 pin staggered DIL, 0.6" width 1 x ICs: R.ohm BA615 408, 14 pin DIL, 0.3" width 1 x 8 digit VFD; single round faced tube 1 x red LED 14 x transistors 9 x diodes 13 x capacitors 33 x resistors 3 x resistor arrays 1 x transformer: CT-134 TDK Japan 1 x fuse 4 x Ever Ready AA-sized rechargeable batteries in a wired pack: RX6 1.2V 650mAh
Boards:	The main board (YLPRO 0002920) sits rigid over the keyboard assembly and is joined by a 13-way block connector. There is on diode on teh keyboard assembly. The main board is amazingly packed with loads of components.
Construction:	Remove the single screw from the rear and the back section will lift away. The rechargeable batteries are screwed to the rear section with a grey plastic cover.

Logic comments:	The (C) button is used once to clear an entry and a second time to clear the whole calculator
	Overflow on number input is suppressed as inputting a ninth digit is ignored
	An overflow shows the result and all eight upper (left hand) comma marks alight and is recoverable using (C)
	Divide by zero shows "' ' ' ' ' ' ' '0." and is recoverable using (C)
	There is automatic constant on multiply and divide only
	Negative numbers are shown by a pin-point red LED to the far bottom left of the display thereby allowing full eight digit negative numbers.
	Logic is reverse Polish Notation: to do 3-6 key in (3)(+)(6)(-)
	Memory is a simple switched accumulation. When on, all results showing when (=) is pressed are added to the memory
	There is no indication of memory - you have to remember it
	You can switch between Floating (F), or fixed two/four digit (4/2) result modes.
	It suffers the pseudo fixed decimal bug: key in (1)(+)(0)(.)(0)(0)(0)(+) to give "1.000" which remains as a fixed three digit decimal until more digits are needed or multiply or divide are used.

	This scan shows the front of the calculator removed. You can see the small blue connecting block in the middle area which connects to the keyboard assembly. There are loads of components crammed impressively into a small board. Notice the plastic display shroud which not only holds the VFD tube in place but has a hole for the single red LED as well. The lower section is taken up with the screw-on batter cover Notice also the typical staggered pin configuration of the Rockwell main IC.