Canon Palmtronic LD-8s

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Calculators: Handheld: Palmtronic Canon 8s (aka LD-8s)


		Size (approx):	70mm x 117mm x 13mm (w x h x d) Weight 72g not including batteries
		Power:	3.0V DC using 2 x AAA size batteries. It accepts an adapter/charger (3V DC 0.2W) through a socket on the top side to the far left. The battery compartment lid is also the battery holding case. The on/off switch is on the left hand side in line with the Canon name.
		Case:	The very slim case is two-piece smooth black plastic. It is angularly shaped with rounded front vertical edges with the whole of the front covered in brushed aluminium panels. A metallic silver and black label bears the make and model number and sits in its own recess. The keyboard surround is shiny brushed aluminium. The neutral display filter is flat, flush and shaped like the case and gives a clean bright image. The springy keys are long travel with a soft click and work very well.
		Display:	8 digit blue VFD with a ninth digit for negative and error indicators.
		Features:	Standard four functions with percentages and square root
		Age:	1977
		Manufacturer:	Canon Inc., made in Japan. Serial number from the sticker on the inside of the battery compartment is 647657. Also own 689593.
		Comments:	This is a calculator with a slim and metallic design that was to be common right up to the mid 1980s. The blue and silver theme works well. The original case is a wallet style cover with the calculator sitting on the left held by a PVC band and tray. It is made from black (outside) and silver (inside) soft plastic with “Canon Palmtronic” silver printed on the front and back. The logic is OK with good recovery but is let down by negative square roots. Interesting to see (below) that this uses the same IC as the LD-8Rs but the square root function switched on and the memory switched off.

Components:	1 x cpu; Texas TMS1042NL KDSN 7727 (week 27 of 1977), 28 pin DIL, 0.6" width black plastic 1 x 9 digit VFD unit single tube flat face; itron FG95D6 Japan on mini-board: 1 x transistor 4 x diodes 5 x capacitors 3 x resistors 1 x transformer
Boards:	Construction is all on one board (EG2-0134) which is fixed to the front with one screw. A small piggy back board handles the power components.
Construction:	Very difficult to open as it is held together by internal lugs and the slim case is not very flexible - damage is highly likely so be careful. If you must, try to pop one of the central side lugs by pushing in the side of the back whilst levering it apart with something not too hard. There is a second lug on each side, lower down. Eventually the back will lift off by hinging around the top.

Logic comments:	The (CI) key is used to cancel an entry whilst the (C) clears the whole calculator
	Input overflow is suppressed, inputting a ninth digit is ignored.
	Negative numbers are shown with a "-” 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 zero and “C” in the far left (ninth) digit and is recoverable using (CI)
	Overflow shows the result and “C” (or “E” if negative) in the far left (ninth) digit and is recoverable using (CI)
	Negative square roots are allowed and result in a negative number

	The scan on the inside shows what measures Canon went to in order to fit all the workings in such a slim case. The IC pins have been bent outwards to "surface mount" it. There is a cut-out on the mini board at the bottom to let the transistor sit in. And finally, the keyboard assembly is actually the reverse of the cpu board; the connectors at the far bottom right are actually the (0) key. Compare this with the Canon LD-8Rs inside - two less diodes and the same IC.