Early
Electronic
Calculator
Desktop Calculator Photo Gallery

Gallery 1  |  Gallery 2  |  Gallery 3  |  Gallery 4

Click on a photo for a larger version in a new window. Click on a model name for more details in a new window.

Canon 130
1966
Logic Technology: DIS
Memory Technology: DIS-FF
Display: IDL

The first calculator from Canon and one of the first electronic calculators. Constructed from discrete Germanium transistors and diodes.

Canon 161
1966
Logic Technology: DIS
Memory Technology: DIS-FF
Display: IDL

A slightly enhanced version of the Canon 130: 16 digits instead of 13, and an additional accumulating memory.

The 161 and 130 are unusual for their period in that they implement a full floating decimal point in which both operands for an operation may be shifted up or down to bring them into alignment. There is no switch to set the decimal point position, in contrast to most electronic calculators of this era. While a considerable amount of logic and complexity is dedicated to achieving this facility, it is nonetheless rather lack-lustre in its thoroughness, leading to some odd and confoundingly erratic behaviour.

Canon Canola 120
1967
Logic Technology: DIS
Memory Technology: DIS-FF
Display: IDL

Information for this unit was provided by Shigeru Masuda of Japan. Much as Jean Campioni with his Canon 130S, Masuda was able to use the Canon 161 schematic to assist in servicing the 120, and then sent along the information presented here.

The Canola 120 is a variation on the Canon 130, the 120 having 12 digits instead of 13. There are some minor alterations in the keyboard layout as well.

Canon 130S
1968 ?
Logic Technology: DIS
Memory Technology: DIS-FF
Display: IDL

Information for this unit was supplied by Jean Campioni in Belgium. Jean's unit was not functioning. Starting with the Canon 161 schematic and after performing some more reverse engineering of portions of the 130S, Jean traced the faults to some bad Ge diodes and was successful in repairing the unit to full function.

The 130S is essentially a repackaging of the Canon 130. The printed circuit boards and mechanical design were redone. Notably the displays are mounted on the circuit boards in the 130S, avoiding the large bundle of wires from the boards to displays present in the 130.

Casio AL-1000
1968 ?
Logic Technology: DIS
Memory Technology: CORE
Display: NIX

The unit shown in the photo is my reconstituted unit. What I received was actually just the card cage and a chopped off keyboard. The case and power supply were missing. A replacement power supply was constructed and some plexiglass and aluminum used to hold it all together. I was not inclined to try to recreate a full case, rather this unit serves as a display of the internals of a discrete-component calculator from the 1960's.

This calculator model appears to be very sophisticated for its age, with it's programmability and 4 memories. However, it suffers from a poorly designed user interface which limits it's capabilities.

Sharp Compet 17
1968
Logic Technology: DIS,SSI,MSI
Memory Technology: MSI-MOS
Display: NIX

An early JMOS-based implementation.

Canon 163
1969
Logic Technology: SSI
Memory Technology: DELAY-MS
Display: NIX

This model uses a magnetostrictive delay-line for memory, but more exceptionally a novel technique with the delay-line is employed for register management. There are two write transducers on the delay-line, at different positions on the line, making a short loop and a long loop. One of the registers cycles on the short loop while the others cycle on the long loop. With another trick of shortening the long loop by one bit, the bit interleave of the long-loop registers varies in relation to the short-loop register, and it becomes possible to vary one of the operands in add/subtract cycles simply by making a selection in time rather than doing a full multiplex/demultiplex of all the registers.

Some logic in the keyboard encoding provides for detection of simultaneous depression (rollover) of adjacent keys, to catch some user entry errors.

Commodore DAC-612
1969
Logic Technology: DIS,SSI,MSI
Memory Technology: MSI-MOS
Display: GDI
OEM: Casio

As the 1960s ended and headed into the 70s, one branch of popular design headed off into the tacky. With earth tones in glossy plastic and fake-woodgrain mac-tac, this has got to be the ugliest calculator ever produced. Otherwise notable for early use of a 7-segment display, in the form of individual gas-discharge tubes. Note the half-height zero in the display.

Based on info from Rick Bensene, this would be another repackaged Casio calculator. The logic and keyboard are that of the Casio 122 (see Onno's Casio 122) with the 7-segment display replacing the Nixies of the 122. "Model 122" labeling can also be seen on the PCBs.

Facit 1123
1969
Logic Technology: SSI
Memory Technology: MSI-BIP
Display: NIX
OEM: Sharp

An unusual feature of the model is lamps in the multiply and divide keys which illuminate to indicate the according operation is pending. While a curious feature in itself, it is actually part of the provision of a 'constant' feature. The lamps remain lit after the completion of the operation, and another multiply or divide can be performed with the earlier second operand. Pressing the += key a second time after completion of an operation clears the constant state, indicated by the lamp turning off.

A cute internal technical aspect of this model is a two-speed clock. The master clock is an astable flip-flop, but with - so to speak - two flip sides and one flop side, with different timing components connecting the two flip sides to the flop side. The slower flip side is enabled for idle display, while the faster flip side is enabled during calculation.

Casio 121-B
1970
Logic Technology: DIS,SSI,MSI
Memory Technology: MSI-MOS
Display: NIX

This page is based on information and photos supplied by Mick Metselaar in the Netherlands. Mick did a reverse engineering of the calculator to assist in repairs. Mick also provided some notes about his efforts.

There is no decimal point key on this calculator, so only integers can be entered. The decimal point is, however, displayed appropriately for the result of divisions. Eliminating so much decimal point management simplifies the control state machine considerably. This, together with the use of several MSI IC's, contributes to the relatively low component count of the 121-B.

Monroe 925
1970
Logic Technology: SSI
Memory Technology: DELAY-MS
Display: NIX
OEM: Canon

This model is actually OEM'd by Canon. It shares some implementation aspects with the Canon 163, such as the IC-series used, the use of a magnetostrictive acoustic delay-line for the register memory, and two write transducers on the delay-line for changing the register bit interleave.

Sony SOBAX 2500
1970
Logic Technology: SSI
Memory Technology: DELAY-MS
Display: NIX

This calculator is based on a small IC family proprietary to Sony. Unfortunately these ICs have a propensity to fail (see the notes about the ICs), making it difficult to keep these calculators functional. I received two units and was originally able to restore both of them to functionality, but one has since been relegated to being a sacrificial unit for ICs.

Notable technically for the use of a magnetostrictive delay line in longitudinal mode, in contrast to the more usual torsion mode. Also, a channel slice in the delay-line is filled with a fixed pattern at power-up. The bitstream from this channel feeds a phase-comparator in a Phase-Locked-Loop arrangement with the master clock as VCO. The master clock is thus tweaked to keep it in sync with temperature variation of the delay-line latency.

Gallery 1  |  Gallery 2  |  Gallery 3  |  Gallery 4



  Desktop Photo Gallery
Calculators | Integrated Circuits | Displays | Simulations
EEC
bhilpert