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Victor 1800 Desktop Calculator

Updated 1/6/2014

This Victor 1800 a part of a series of different machines in the line of 1800 calculators introduced by Victor Comptometer Corporation in 1971. Apparently a number of different machines were made under the '1800' designation, with varying model numbers and capabilities. The model number of this machine is 18-1441. The 18 signifies the 1800 series, with the first two digits (14) of the model number defining the number of digits of capacity of the machine, and the last digit signifying that the machine has one memory register. Apparently three different models of the 18-144x calculators were made, the 1440, with no memory functionality, the 1441 exhibited here with a single memory register, and the 1442, with an additional memory register. Other 1800-series machines were made, including two 18-154x series machines, the 18-344x printing calculators, and the 18-1721 Scientific calculator.

Inside of the Victor 1800

This machine dates from the late 1971 timeframe. It uses a 6 chip Large Scale Integration (LSI) chipset made by Rockwell for its brains. All of the LSI's are dated in the October 1971 timeframe, and other components in the machine share similar dating. This makes the Victor 1800 a fairly early LSI machine.

Closer View of Rockwell LSI's

The Rockwell chips are numbered 10177, 10178, 10179, 10180, 10182, and 15000, and are packaged in 42-pin ceramic packages. The chips are mounted on a fiberglass double- sided circuit board, along with basic discrete support components such as diodes, resistors and capacitors. The main brain board connects to other areas of the calculator via flexible ribbon cables. Even the power supply connects to the main board via a flexible cable. The power supply and main board are mounted to the base of the case, with the keyboard, display, and display driver circuits mounted to the top part of the case.

The Gas-Discharge Display of the Victor 1800

Hybrid Modules Used as Display Drivers

The 1800 uses a gas-discharge display panel similar to a Burroughs Panaplex, however, it appears to be made by someone else (can't discern any manufacturer), and is of a somewhat different design than the Burroughs panels. Burroughs Panaplex panels use a clear metallized electrode in front of the segments, whereas this panel has an wire grid (similar to that of a Nixie tube) in front of the segments. The panel has 16 positions, with the right-most digit position used for indicating sign (-), and the far left position serving as an indicator for overflow conditions (F). The display panel has a fairly large circuit board crammed with hybrid devices that serve as the display drivers. The hybrids contain a ceramic substrate which contains passive components, along with discrete high-voltage transistors which provide the high-voltage switching to drive the gas-discharge display. Display digits are formed out of nine segments. The standard 7-segment arrangement is modified to add two vertical segments that allow the '1' to be displayed centered within the digit. Each digit position also contains a decimal point. The display logic performs both leading and trailing zero suppression.

Victor 1800 Keyboard Layout

The Victor 1800 is a four-function calculator, with one memory register. The calculator operates pretty much as expected for a machine of this vintage, with the "+" and "-" keys operating adding-machine style. For example, to perform 10 - 8, one does 10 + 8 -. Multiplication and division use the "=" key to generate the result. The machine has a full-time constant, which operates in all four functions. This can be demonstrated by pressing "[1] [+]", followed by repeated presses of the [+] key, which results in the display incrementing by 1 for each press of the [+] key. A constant in all four functions is a useful ability that is not shared by many calculators from this era. The memory functionality of the machine is quite nice, with [M+] and [M-] keys adding/subtracting the content of the display to/from the memory register without affecting the display. The [=+] and [=-] keys serve to terminate a multiply or divide operation (like the [=] key), but also adds/subtracts the resulting answer to/from the memory register, leaving the result of the multiply/divide on the display. This is very useful for sum-of-products types of operations. When the memory register is non-zero, a small round indicator on the right side of the display panel (labeled "M1") lights. Rounding out the memory functions, the [MR] key recalls the content of the memory register to the display, and the [MRC] key recalls, then clears, the memory register. The [EX] key exchanges the operands of math functions, IE: [4] [÷] [8] [EX] [=] will result in 2 (having performed 8/4 rather than 4/8). The [C ALL] key clears everything except the round-off setting, including the memory register. The [C] key clears overflow indications, as well as clearing the display to allow entry errors to be corrected.

The Unusual "Round" Function Setting (showing the machine is set to round to 9 digits behind the decimal)

The 1800-series machines are full-floating decimal point machines. The decimal point is automatically placed at all times to provide maximum precision. However, the machines add an unusual twist to the picture by providing a "Round Off" function. Two keys on the keyboard with 'arch' symbols on them, one [arch SET], and the other with just the [arch]. These keys are used to set the position of, and perform, a round off function. The [arch SET] key, when pressed (see image above), switches the display to show a single digit from zero through nine, indicating the current number of digits behind the decimal point that the machine will round off to when the [arch] key is pressed. Pressing any digit from zero through nine while holding down the [arch SET] key will set a new rounding position for the machine. Releasing the [arch SET] key restores the display to its original content. Once a rounding setting has been established (the machine by default powers up with the rounding setting at 2 digits behind the decimal point), any time that the operator wishes the number on the display to be rounded-off to the desired setting, the [arch] key is pressed, and the number on the display is immediately rounded to the selected number of digits.

Overflow Indication (F)

The 1800 is a very fast machine, with virtually instantaneous results, even on the "all-nines divided by one" test. A guess would be that the all nines division takes perhaps 60 to 80 milliseconds...fast enough that the result seems virtually instant. During calculation, the display is quiet, with no spinning of the digits or other indication that the calculator is busy. The machine is very good about detecting overflow conditions, by displaying an "F" in the left-most position of the display, and locking the keyboard. Overflow detection is also activated when division by zero is attempted. Pressing the [C] key when overflow lockout occurs clears the display and the overflow condition.

This machine was found at a flea market by my aunt, who is always on the lookout for interesting old calculators for me when she's out treasure-hunting. The machine is in like-new condition -- whomever owned it took very good care of it. Total price paid: $0.10.


Text and images Copyright ©1997-2014, Rick Bensene.