Casio Deluxe Memory

Size (approx):	156mm x 82mm x 30mm (w,h,d) Weight 186g excluding batteries
Power:	6V DC, 4 x AA size batteries. It accepts an adapter (AD-4145, 0.28W) through a socket on the top side about 1cm from the left. The on/off switch has a third position for "T", total.
Case:	Horizontal format two-piece case in black and white smooth plastic. The display escutcheon in black plastic set in its own recess, flush and tilted. A further inset panel has printed model number and reversed out Casio name on a metallic sticker. Large, long travel hollow sounding keys work well and a deep cut groove (read dirt collection area) outlines the key area. A slightly inset neutral display filter gives a bright display with odd "small zero" notation (see below).
Display:	8 digit blue VFD, with no ninth digit for additional display. A shift-display key helps out.
Features:	4 function calculator with total, percentages and display shift for 16 digit precision. Total summation and decrement facility.
Age:	1974
Manufacturer:	Casio Computer Company Ltd. Made in Japan, serial No. 3152882 (on battery cover) and none inside battery compartment on my example.
Comments	One of a range of early, solidly built horizontal calculators by Casio very similar to the later Casio Mini Memory. This one benefits from an eight digit display but strangely keeps the shift key. Logic is let down by unrecoverable errors, divide by zero and quirky memory system.

		Home New Stuff Author Links Guest book Web-log	Adverts Bric-a-brac Calculators Components Ephemera Events	For Sale Glossary History Hit or Miss Radios Transport	Ultra Valves Wanted Metal Puzzles Clocks

Components:	1 x cpu: NEC µPD970C K48236 36 pin DIL (date code August 1974), 28 pin DIL, 0.6" width black plastic 1 x 8 digit VFD display single glass tube: LD8105 1 x transistor unit: vertical 7 pin SIL unit (?) 4 x diodes 9 x capacitors 2 x resistor arrays 6 x resistors 1 x transformer: Fuji MPS0602 4H-13 Pat. No. 427559 (date code August 1974)
Boards:	The keyboard assembly (ref D8Z-E4-1 B) sits lose on top of the battery compartment and is joined to the main cpu board (ref D8Z-1C LD8105) by 12 stiff wires. The former is L-shaped to avoid the battery compartment. The whole assembly sits lose in the case.
Construction:	Remove the single screw on the right hand side and very gently squeeze in the black section to release the lugs one by one. Not for the faint hearted - so do not attempt if you want to keep the calculator pristine. The front will lift off but the lower left hand edge can be really tricky as the lug butts onto the board.

Logic comments:	The (C) button is used to clear last entry of a number and the (AC) to clear the whole calculator.
	Overflow on number input is suppressed, typing in a seven digit number ignores the seventh digit.
	An overflow error is flagged with the answer displayed and viewable using the shift key (>) and is not recoverable
	Divide by zero error is ignored and calculation can continue with the zero result.
	There is automatic constant on multiply and divide only
	To add to the memory switch to "T" mode and every (=) signs adds to the memory. To subtract from the memory use the red (=) key. (AC) clears the memory and there is no indication - you have to remember it.
	Negative numbers are shown by a "-" in the immediate left digit. A result which is eight digits long and negative results in an unrecoverable error but you can see the answer by use of the shift (>) key.
	It suffers the negative zero bug: key in (1)(-)(2)(=) to give "-1" now (+)(1)(=) to give "-0"
	It suffers the divide to negative zero bug: key in (0)(-)(1)(=) to give "-1" [which shows the extra internal digit of precision] now (/)(1)(0)(=)(=)(=) etc until you get "-0.000000" then (=) will give "-0"