Sanyo CX-8001

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Calculators: Handheld: Sanyo CX-8001


	Size (approx):	85mm x 148mm x 38mm (Max) (w,h,d) Weight 210g excluding batteries
	Power:	6V DC using 4 x AA size batteries. It accepts an adapter (DC 4.6V 1.0W three pin connector) through a socket on the top side to the far right. The battery compartment has a ribbon pull to help battery removal.
	Case:	Made from a sturdy two-piece buff-coloured smooth plastic case. There are two end sections in matt black plastic. The blue plastic display filter is titled at about 20 degrees and printed with white text for the numeral positions and indicator labels. Two additional LEDs poke out from cut-outs. Below this is a black printed metallic sticker with the brand and witch label. A further black smooth plastic panel acts as a keyboard surround. The keys are large, wobbly, long travel and hollow sounding. The number keys are convex whilst the other (yellow) keys are flat.
	Display:	8 digit blue VFD with no ninth digit. Two separate red LEDs for overflow and negative indicators.
	Features:	Standard four functions with register exchange and switched constant
	Age:	1973
	Manufacturer:	Sanyo Electric Co., Ltd. Made in Japan. Serial number 82202325.
	Comments:	Solid and bulky calculator with keys that feel like the earlier desktop machines. Quaint double LEDs for indicators and a clear blue display are very nice. RPN logic is archaic, no recovery and off constant function makes this is bit if a white elephant. The original case is black soft plastic with a zip that goes 1/6 way up on left, across the top and 2/3 way down on the left. It has Sanyo embossed on the front and Japan embossed on the back. This is a very early three-chip calculator that is crammed full of components.

Components:	1 x cpu; NEC D2710 K2X636 28 pin DIL, 0.6" width 1 x IC: NEC µPD261C K29106 20 pin DIL 0.6" width 2 x ICs: Toshiba TM4352P 14 pin DIL 0.3" width (display drivers?) 1 x 8 digit VFD; single glass tube round faced: Futaba 8-CT-01A 5 x transistor 16 x diodes 11 x capacitors 5 x resistors 35+ x resistors (I think as they are more like tantalum bead capacitor cases - small blobs) 1 x transformer and power stepper module; R-W77125 MCT4204 3B05 (batch 5 (?) of February 1973)
Boards:	The main cpu board sits loose on the bottom of the calculator and is joined to the main keyboard assembly via strong wires.
Construction:	Remove the two screws from the rear. This does absolutely nothing as the case is held together by internal lugs. It took me ages to eventually pop a side by pushing in the front section and levering out with a fingernail. I would not recommend trying as it is very easy to damage your calculator. The front lifts off.

Logic comments:	(CK) clears the last number entered whilst (CA) clears the whole calculator
	Input overflow is not suppressed, inputting a ninth digit results in an overflow that is not recoverable
	Negative numbers are indicated by a separate red LED in the lower middle section of the display thereby allowing eight digit negative numbers
	There is selectable constant on multiply and divide
	The calculator operates reverse polish notation; to do 3-7 key in (3)(+=)(7)(-=) to give "-4". Note if you have the constant switched on you will get "-7" as the constant appears to switch of addition and subtraction!
	Divide by zero shows no display but the overflow LED on and is not recoverable
	Overflow shows no display but the overflow LED on and is not recoverable
	(RC) is register exchange and will swap the current display for the last number entered

	This scan if the main board with the front of the case removed shows how crammed everything is. You can just see the display driver ICs underneath the VFD tube and the two red LEDs in the middle. Above the display you can see (from left to right); transformer, voltage stepper circuit in card sleeve, power transistor and the three pin socket. Notice the little blobby two-coloured components that are too small and too numerous to be capacitors, so I think they are miniature resistors.