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Calculators: Handheld: Palmtronic Canon 8Rs (aka LD-8Rs)
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| Size (approx): |
70mm
x 117mm x 13mm (w x h x d) |
| 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 automatic memory |
| Age: | 1976 |
| Manufacturer: | Canon Inc., made in Japan. Serial number from the sticker on the inside of the battery compartment is missing on my example |
| 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 logic is good with good recovery and bugs. Interesting to see (below) that this uses the same IC as the LD-8s but the square root function switched off and the memory switched on. |
| Components: | 1 x cpu; Texas TMS1042NL KDSN
7638 (week 38 of 1976), 28 pin DIL, 0.6" width black plastic 1 x 9 digit VFD unit single tube flat face; itron FG95D6 Japan 1 x transistor 6 x diodes 5 x capacitors 3 x resistors 1 x transformer |
| Boards: | Construction is all on one board (EG2-0133) 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) | |
| Memory is automatic - being the sum of and (=) key | |
| Memory is indicated by an upper "n" in the far left (ninth) digit and is cleared by pressing (RM/CM) twice | |
| No bugs found |
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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.
Compare this with the Canon LD-8s inside - two extra diodes and the same IC. |
