Anita 810

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Calculators: Handheld: Anita 810

		Size (approx):	70mm x 120mm x 23mm (w,h,d) Weight 126g excluding batteries
		Power:	4.5V DC, 3 x AA size batteries. Accepts an adapter/charger (not defined) through a socket on the top side in the middle. It is a very odd two section square socket. Also, do not set the switch to battery picture whilst on adapter as this will discharge the batteries.
		Case:	Leading edge or what! The main case body is a three-piece taupe coloured smooth plastic case with rounded box key surrounds. A sliding u-shaped metal back is not painted like in some models by Anita. The back is pushed up to reveal the battery compartment and inner information label. A brushed aluminium wrap around panel sits in its own recess and is printed black with abstract symbols for adapter/battery power (on/off) and floating/round-off. The red display filter sits (almost) flush and gives a clear bright image. The designer round keys are short-travel squishy type but work well.
		Display:	8 digit flat multi-point red LED with a ninth digit for negative and error indicators.
		Features:	Standard four functions and percentages. Floating and two digit switching. Reverse Polish Notation input.
		Age:	1972 to 1974 (this example is chip date-coded for early 1974 with high board revision numbers)
		Manufacturer:	Sumlock Comptometer Ltd, Uxbridge, Middlesex, UK. An embossed number on one side may be the serial number: 8102461.
		Comments:	Lovely early design that is probably made by Adler (as it is very close to the Adler 81) who were known for their sliding back models. Nice display but pain in the neck early RPN logic. Otherwise the logic is very good with no bugs and good recovery. The original case is stiff brown fake leather with flip over top flap and front tuck-in band. The construction is ingenious, cramming loads into three neatly packaged boards. Every collection should have one of these.

Components:	1 x cpu: Rockwell 15332 A1032PD 7411 (date code week 11 of 1974) 42 pin staggered DIL, 0.6" width 1 x 9 digit red flat LED display 20 x transistors (9 for display drivers) 4 x diodes 4 x capacitors 0 x resistor arrays 22 x resistors 1 x transformer
Boards:	The keyboard assembly (2016 PC 810 Keyboard Iss. 2 TB3051) is attached to the first (cpu) board (Ref 1970 PC Iss. 1 MAIN BD TB3754) via 13 strong wires which is attached to the second board (Ref. 1852 PC Iss. 11 TB3528 Convertor BD) via 5 strong wires in the same place. The latter board has three circular cut-outs to allow the tantalum bead capacitors and transformer to sit through and minimise the thickness. The two boards are kept apart by sliders in the main case sides.
Construction:	By gently pushing out the metal sides you can fully remove the u-shaped back. Surprisingly the underside of the main board is then exposed. Remove the two side screws and the base drops off (be careful not to lose the two square washers). The upper and side section then pull away to leave the keyboard attached to the main assembly.

Logic comments:	(C) is used once to cancel the last number entered and a second time to clear the whole calculator.
	Input overflow is suppressed, inputting a ninth digit is ignored
	Negative numbers are shown with a minus in the far left (ninth) digit thereby allowing full eight digit negative numbers
	There is automatic constant on all four functions
	Divide by zero shows a "C" in the far left (ninth) digit and is recoverable using (C)
	Overflow shows the result and "C" ("E" if negative) in the far left (ninth) digit and is recoverable using (C)
	This is a RPN logic calculator; to calculate 3-4 you enter (3)(+)(4)(-) and only use the (=) key for multiply and divide
	The semicircular switch is a round up/down to two decimal places switch. It appears to function on percent, multiply and divide only
	The round-off switch will round up or down to two decimal places and the display is limited to two decimal points until the number gets too big

With the sliding back removed you can see the upper (power supply) board of the triple layer assembly.

Note the three cut-outs for the two tantalum bead capacitors and one transformer to sit through. This reduced the thickness of the whole assembly by those precious few millimetres.

The text "Issue 11" on the board implies this is quite a late revision in a line of many.