How to use this Canola calculator?

[Julesomega]

The Canon Canola L1216 was introduced in 1974, using a single-chip device, the NEC µPD284C, shortly after the Japanese manufacturers had started importing microprocessors from Rockwell

The build quality is beautiful and obviously intended to allow indefinite maintenance, and the keyboard switches use reed switches activated by a magnetic plunger on each key. Mine must have been a skip find, and when I recently retrieved it from storage it was in full working order - a few sticking switches needed light lubrication

It can be made to do a few simple procedures, using the =+ or =- keys, and the result is always added to memory. There is a "sig fig" slider for the results. The K key is used for mult/div by a constant, and I have yet to work that out. What I do not understand are: the function of the "%±" key; the slider for "5/4"; the slider for "AM"; and why there is a mechanically moveable pointer system above the (orange) LED display, shown on this image as pointing down between digits 1-2, 4-5, 7-8, and 10-11

Canon Canola L1210 Electronic Desktop Calculator

The Calculator Wars: A video history of Japan's electronic industry (Part 3)

[TonyDuell]

A few guesses :

The 5/4 switch is to do with rounding. In one position it will simply truncate the number (2.1 -> 2, 2.8 ->2, say), in the other it will round (2.1 -> 2, 2.8-> 3). Quite how you get it to round I don't know, some Casio machines used the -= key after division for this.

The %+- key I would guess is for adding or subracting a percentage, for example for adding VAT. Try something like <number> += <percentage> %+- +=

The mechanical pointers on the display digits are simply to provide 'commas' every 3 digits, so you can easily read the display as 1,004,567 or whatever.

[fetteler]

Sorry not to be able to help with any of your questions but what a super calculator!

Steve.

[SiriusHardware]

The functions of the calculator will be entirely determined by that NEC chip which presumably is a dedicated calculator IC. If you can find the datasheet for the NEC IC, that may yield clues.

Lovely machine, display is made to be easily replaceable, magnetic reed switch keys, very easy to fix even now. Definitely a keeper.

[Julesomega]

Yes, one to keep! I will keep it on the desk, ready for use by virtue of having a mains switch on the side. Thanks Tony, the "5/4" switch rounds up when selected, or down when showing 'down'. The "AM" switch selects 'add result to memory' - logical really! I haven't had any joy with the % key but I'll keep trying

The 'K' switch can be used to select either the 1st or the 2nd-entered number as the constant - handy also for powers; pity it doesn't do sqrt.

[G6Tanuki]

Not sure if this is the same on your calculator but the ones I remember you entered a number then pressed the +/-% key. This sets the percentage you want to add or subtract.

You then enter a second number and press the +/-% key which adds or subtracts the preset percentage from this number and displays it.

Used for doing stuff like adding 17.5% VAT to a set of prices.

[Julesomega]

Just tried that but nothing happens. The display is not reset, so if you press "20 > % > 77" you have only entered 2077

[G6Tanuki]

Try something like

-20%=

To set it to subtract 20%

Then enter a number and hit =

[Julesomega]

Thanks, I tried that and it simply divides the entered figure by 100, fair enough for a percentage but not quite as innovative as I had hoped!

[G6Tanuki]

There must be _some_ way to preset the percentage.. Try hitting = twice after entering the percentage and the % key...

[fetteler]

n%=K or K=n% ?


Steve

[Julesomega]

Yes, that works

[fetteler]

Hurrah

I cast my mind back over the years and tried to remember what I used to do on an old desktop calculator we had in out crew room! I'm happy to help.

Steve.