Prinztronic SC5001M Scientific

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Calculators: Handheld: Prinztronic SC5001M Scientific

		Size (approx):	75mm x 143mm x 23mm (max) (w,h,d) Weight 150g excluding batteries
		Power:	6V DC, 4 x AA size battery. Also accepts adapter (6V, 100mA, centre positive) through a socket on right side in line with the branding.
		Case:	Solid but slightly squeaky two-piece case. Dark brown base and (originally) white upper half. Metal keyboard surround has been painted black with silver text and logos. Switch for on/off and degree/radians. Green display filter is tilted at about 25 degrees and is lightly shielded by raised sides. Buttons are short-travel with a positive click and work well on this sample.
		Display:	8 digit green VFD with a ninth digit for minus indication
		Features:	Standard functions, two function memory, change sign, inverse, trigonometric functions, logarithms, square roots, squares, pi, logs and powers. Two levels of parenthesises but no percentages. Degrees and radians. Six digit plus 2 mantissa display.
		Age:	1976
		Manufacturer:	Prinztronic, made in Taiwan. Inside Battery cover states Model No. 1459, Serial No. 380819. I have another that just has a serial No. 0247826.
		Comments:	Early scientific calculator with a bright green easily readable display. Takes about four seconds to do e^x or y^x. Unusual in that the input of a number goes from left to right, not the normal other way. Otherwise the logic is only let down by lack of recovery and simple memory. The Memory Store button (MS) at the top right looks like a bit of an after thought. Very similar to the SC4001M and is very similar to Qualitron models. Original case is soft black plastic with flip over top and popper closing on the upper front.

Components:	1 x IC: Rockwell A6500CA 7610 (week 10 of 1976), 42 pin staggered DIL, 0.6" width black plastic with metal cap 1 x 9 digit VFD module single glass tube flat faced; Futaba 9-ST-10 6a (Date code January 1976) 0 x diodes 2 x capacitors 3 x resistors 2 x resistor arrays 1 x transformer; Best Choice DCV-4055 7616 (week 16 of 1976)
Boards:	The main cpu board (Q1-/450A-3) is face down and attached to the front by two more screws. It is joined to the keyboard assembly with 13 wires in a plastic sleeve. The keyboard is attached to the front with six screws. The main cpu board has lots of unused holes so I suspect it is generic to many models.
Construction:	Remove the two screws from inside the battery compartment. There is a third screw underneath the rear label which is impossible to remove without damage. The back lifts off easily as there are only lugs on the top and left (from the rear) sides.

Logic comments:	The (C) button is used to clear last entry of a number whilst a second press clears the whole calculator, so it is really a (CE/C) key
	Input overflow is suppressed, keying in a ninth digit is ignored
	Overflow shows "0.0.0.0.0.0.0.0.0.", negative or positive which is not recoverable
	Divide by zero shows "0.0.0.0.0.0.0.0.0." which is not recoverable
	There is automatic constant on all four functions.
	Negative numbers are flagged by a "-" sign in the far left (ninth) digit thereby allowing full eight digit negative numbers
	Square roots of negative numbers are not allowed and result in error as above
	There is no indication of memory store - you have to remember it.
	The only way to overflow the memory is by keying in something like (8)(9)(EXP)(9)(9)(MS) which flags the error and stores nothing
	Memory clear is by keying (0)(MS)
	The change sign can be used in mid number entry but not before
	A switch allows you to select between radians [RD] and degrees [DG]
	Trigs and logs appear to be limited to five decimal places of accuracy
	No major bugs found