Panasonic JE-8501

		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

Calculators: Handheld: Panasonic JE-8501 (aka 8501)

		Size (approx):	79mm x 130mm x 26mm (max) (w,h,d) Weight 128g excluding batteries
		Power:	3.0V DC, 2 x AA size batteries, 0.4W. It accepts an adapter (JL-046, 047 or 048) through a socket on the top side in line with the model number.
		Case:	Two piece case, the rear section being bowl shaped white glossy plastic whilst teh front is a matt black plastic. An oversized neutral plastic display filter is inset and very slightly tilted in its own escutcheon. A black printed metallic label sits in its own fill-width recess and contains the brand and model number. The matching matt black plastic keyboard surround has embossed lettering for the on/off switch. Subtle coloured keys are soft and squishy and have a soft click. The back has a recessed panel labelled “name” for you to put your own sticker in.
		Display:	8 digit blue VFD, with a ninth digit for minus, memory and error indication.
		Features:	4 function calculator with percentages, change sign square roots and four-function memory
		Age:	1975
		Manufacturer:	Matsushita Communication Industrial Co., Ltd, made in Japan. Serial number on the inside of the battery cover is 5X101089.
		Comments:	High quality feel to this sturdy calculator with unusual two-piece case design. The logic is not too bad with good recovery (if odd) but let down by negative square roots and no input suppression. The original soft black plastic cover is open topped with front and back half-moon cut-outs. It is embossed with Panasonic Electronic Calculator on the front. This calculator was also branded the National Panac M-1.

Components:	1 x cpu: NEC µPD946C R58766, 28 pin DIL, 0.6" width 1 x 9 digit VFD single tube flat face: Futaba 9-ST-10 5J (September 1975) 3 x transistors 6 x diodes 7 x capacitors 8 x resistors 2 x resistor arrays 1 x transformer: TDK CT-300
Boards:	The keyboard assembly (5902345) sits loos on top of the battery compartment and main board (YLPRD0004900). The whole assembly sits lose in the case with quite a snug fit. The two boards are joined with a 13-way ribbon cable and two power cables.
Construction:	Remove the single screw from the back and gently lift off the front section. Interestingly, the display filter has an additional circular window that looks like it was designed to accommodate a point light indicator.

Logic comments:	The (CE) button is used to clear last entry of a number and the (C) clear the whole calculator.
	Input overflow is not suppressed; inputting a ninth digit causes and overflow but calculations can still continue with shifted results. It is recoverable by dividing by ten
	An overflow shows the result with a “C” (or “E” if negative) in the far left (ninth) digit and is recoverable by dividing by a multiply of ten
	Divide by zero results in zero and a "C” in the far left (ninth) digit and is not recoverable
	There is automatic constant on all four functions
	Negative square roots are allowed and give a negative result
	Negative numbers are shown by a "-" in the far left (ninth) digit thereby allowing full eight digit negative numbers.
	The change sign (+/-) key can be used in mid number entry but not before
	Memory store is indicated by the decimal point of the far left (ninth) digit
	Overflow in memory is not indicated until you recall the shifted result (with a "C" or "E" attached). This is recoverable by dividing by multiples of ten.
	No bugs found

Inside

This image shows the front removed and the majority of the main cpu board obscured by the keyboard assembly.

At the top of the keyboard you can see the ribbon cable attaching to the main cpu board. The main board is covered with printed text for component and pin identification.