Prinztronic Financial

		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 Vales Wanted Metal Puzzles Articles Clocks

Calculators: Handheld: Prinztronic Financial


		Size (approx):	75mm x 143mm x 32mm (max) (w,h,d) Weight 148g excluding batteries.
		Power:	6V DC, 4 x AA size battery. Also accepts an adaptor (6V 100mA). Socket on right side two thirds up. Adapter socket is centre positive.
		Case:	Solid but slightly squeaky two-piece smooth plastic case. Dark brown base and (originally) white upper half. Metal keyboard surround has been painted black with silver text and logos. 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 negative and error indicators
		Features:	Basic four function with percentages, change sign, square root and many financial functions.
		Age:	1975
		Manufacturer:	Prinztronic, made in Taiwan. Inside battery compartment sticker states serial number. 533166.
		Comments:	Very specialised financial function calculator that looks to have been made by Qualitron. Unusual in that it defaults to two decimal places mode. Logic OK but negative zero bug and negative square roots let it down. Very similar case to the SC4001M and SC5001M and is very similar to Qualitron models. Original case is soft black plastic with zip up side and top.

Components:	1 x IC: Rockwell A4561PB 7520 (week 20 of 1975), 42 pin staggered DIL, 0.6" width 1 x 9 digit VFD module single glass tube flat faced; 9-ST-12 5C (March 1975) made in Japan 7 x diodes 2 x capacitors 4 x resistors 2 x resistor arrays 1 x transformer; Best Choice DCV-4055 7514 (week 14 of 1975)
Boards:	The main cpu board is attached to the front by two more screws. It joins the keyboard assembly via ten wires which is attached to the front with four 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. My example was missing its label anyway so I could look inside. The back lifts off easily as there are only lugs on the top and left (from the rear) sides.

Logic comments:	(CA) clears the last number entered whilst a second consecutive press clears the calculator
	Input overflow is suppressed, inputting a ninth digit is ignored
	There is automatic constant on all four functions
	The change sign can be used in mid number entry
	Negative numbers are represented by a minus sign in the far left (ninth) digit thereby allowing full eight digit negative numbers
	The default display mode is fixed two decimal point which will shift to zero decimal points when required - but you never get more than two
	Divide by zero show "0.00" and an upper "n" in the far left (ninth) digit and is recoverable using (CA)
	Overflow shows the result and an upper "n" (upper "o" if negative) in the far left (ninth) digit and is recoverable using (CA)
	It suffers the negative zero bug; try (1)(-)(2)(=) to give "-1.00" then (+)(1)(=) gives "-0.00"
	It suffers the divide to negative zero bug: (-)(1)(=)(/)(1)(0)(=)(=)(=) will give "-0.00"
	Negative square roots are allowed and result in a positive number
	The (COMP) key is used as a function select; for the square root of nine key in (9)(COMP)(÷) to give "3.00"
	Without having a manual I must guess at all the functions; (COMP) appears to select [or compute] the selected function, whilst (ENT) enters data for a selected function, (n) is number of periods, (i/yr) is interest per year, (i) is interest over period, (PMT) is payment (PV) is present value, (FV) future value (x-bar) is average, (TL) is intercept and (TREND) is the slope, (SELL)(COST)(MARGIN) works out the percentage margin, (sigma) is sum of entries and not sure what (DS) is.