Hanimex BC802

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Calculators: Handheld: Hanimex BC802 (aka BCM803?)


		Size (approx):	76mm (max) x 123mm x 18mm (w,h,d) Weight 106g excluding batteries.
		Power:	3.0V DC, 2 x AA size batteries. Also accepts adapter/charger (3V DC) through a top side socket to the far right.
		Case:	Two-piece matt black plastic case with gloss finish top and bottom ends. The sides have a full-length brushed aluminium panel which gives it a quality feel in the hand. The front top has an inset aluminium panel printed with black to reverse-out the brand and model number. Within this a red plastic display filter is inset, tilted and horizontally convex to give additional magnification. The matt black keyboard surround has embossed labelling for the two switches. The small keys are very short travel with a pronounced click.
		Display:	8 digit red LED (with individual bubble lens) with a ninth digit for negative, memory and error indication.
		Features:	Standard four function with percentages and four-function memory. A further memory summation function is switched.
		Age:	1974
		Manufacturer:	Hanimex, no country of origin, serial number 418738F on a sticker inside the battery compartment.
		Comments:	Rare Hanimex model that may have been given two model numbers (see comments below on the box). LED display is better than most as it is magnified quite large though with the normal limited angle of view. The logic is not bad but let down by the pseudo fixed decimal and divide to negative zero bugs. The original cover is soft black plastic with a flip over top flap and front tuck-in pocket.

Components:	1 x IC: General Instruments (square spiral logo) C-595-1 7423 (date code week 23 of 1974), 28 pin DIL, 0.6" width black plastic 1 x 9 digit LED display 12 x transistors 3 x diodes 5 x capacitors 24 x resistors 1 x transformer
Boards:	The main board (GE 703 REV 1) sits face up on top of the keyboard assembly (E3330 A-22 ETCO) which is fixed to the front. They are joined by 13 lose bent wires and separated by a lose insulating card. The main board is held in place by some plastic side lugs.
Construction:	Very difficult to open so be careful not to damage the case. Use the slot at the bottom rear to try and prize up the rear section. You can then slowly travel up the sides, popping the internal lugs until the back lifts off completely.

Logic comments:	(C/CE) cancels the last number entered whilst a second press will clear the whole calculator
	Input overflow is suppressed; inputting a ninth digit is ignored
	There is automatic constant on all four functions
	Negative numbers are represented by a "-" sign in the immediate left hand digit travelling into the far left (ninth) digit thereby allowing full eight digit negative numbers.
	Overflow shows the result and "C" (or "E" if negative) in the far left (ninth) digit and is recoverable using (C/CE)
	Divide by zero results in zero and "C" in the far left (ninth) digit and is recoverable using (C/CE)
	Memory store is indicated by a "L" sign in the far left (ninth) digit
	Overflow in memory is not flagged and stores the shifted result
	The "S" switch is the memory summation function, when on, all results of the (=) key are added to the memory
	If suffers the pseudo fixed decimal bug: key in (1)(+)(.)(0)(0)(0)(=) to give "1.000" which remains a fixed three decimal digit number until your need more digits or use multiply or divide
	It suffers the divide to negative zero bug: key in (-)(1)(=)(/)(1)(0)(=)(=)(=) etc to eventually give "-0"

The box that came with my sample may be the wrong one. However, it looks the right size and the picture on the front mimics the above calculator perfectly.

Does anyone know if the Hanimex BC802 and BCM803 are one and the same calculator?

The box measures 110mm by 168mm and is 47mm deep. Double tuck-end construction with a two-piece polystyrene box inside for holding the calculator in cover, manual and possible set of batteries. It is printed in red, light blue and black with the part number 28-1002(6). No country of origin but it has a UK price sticker stating £22.95.

With the rear section removed you can see the main cpu board sitting on top of the keyboard assembly. Note the row of transistors used to drive the display. In later models this was replaced by another IC and eventually dispensed with as main CPUs became capable of driving displays direct.

The collection of black wires at the bottom connect to the keyboard.