Canon Canola L1210 Electronic Desktop Calculator
This fairly common desktop calculator is from the mid to late-1973 timeframe. It isn't particularly noteworthy in any way, except that it is interesting that it is a fairly late machine made up of a calculator chipset rather than a single-chip implementation.
Canon Canola L1210 Opened Up
The Canon L1210 uses a two-chip set for its calculating intelligence. Texas Instruments TMC 0321 and TMS 0201 LSI's combine forces to deliver the brains to the machine. A trio of oddly packaged devices (similar to those in the Canon L100S) with an "IC" logo provide the driving circuitry for the Hitachi-made Panaplex-style display, which has 12 digits plus an additonal symbol column at the far right for indicating sign and memory status. The display provides 'comma' indicators located above and to the right of each digit. The chipset takes care of providing placement of a 'comma' every three digits in front of the decimal point. The Panaplex module plugs into the machine circuit board via an edge connector. The power supply is a pretty straightforward transistor-regulated linear supply. The keyboard has full-travel keys which have magnets on thier bases which activate glass-encapsulated magnetic micro-switches. The keyboard connects to the main board via an early version of a flexible circuit board -- a clear plastic sandwich containing copper 'traces'. An edge-card connector is at one end of the 'flat cable' which plugs into fingers on the main board of the calculator.
Hitachi-made H1833C Panaplex-style Display Module
The L1210 provides the standard four functions, with adding-machine style "+=" and "-=" keys for adding and subtracting, as well as for providing the answer for multiplication and division problems. The machine also calculates square roots, and can do percentage mark-up and mark-down functions. The machine also has a memory register, with keys for adding the number in the display to the memory, subtracting the number in the display from the memory, recalling the memory to the display, and clearning the memory register. When there is a number in the memory register, a 'dot' lights up at the right end of the display panel. The "AM" key is a push-to-lock/push-to-unlock key that automatically adds the result of multiplication and division operations to the memory register, useful for 'sum of products' type operations. The machine also has a "K" key, which when depressed, provides a constant function for multiply and divide operations. The machine operates in full floating or a number of fixed decimal point modes (6,4,2,1, or 0 digits behind the decimal point) based on the setting of a slide switch on the keyboard panel. The rounding mode of the machine (round up or truncate) based on the setting of another slide switch. As with most Canon calculators, a 'backspace' key is provided to ease correction of entry errors, along with a "CI" key to clear the display. The "RV" key swaps the display register with the 'hidden' entry register where the first number in an operation is placed when the function key for the operation is pushed. Overflow is indicated by the Canon trademark "left facing arrow" symbol at the far right end of the display. This indicator is a separate incandescent lamp, and is not part of the Panaplex panel.
Closer View of Main Circuit Board
The machine is rather slow, with all-nine's divided by one taking approximately 3/4 second, and square root functions nearly one second. During calculations, the display is blanked with the exception of the 'comma' indicators and the decimal points, which tend to jump around a bit while the machine is busy calculating.