Adler 804 Electronic Calculator

The Adler 804 is a "clone" of another machine in the museum, the Miida MC840. The cabinet and general style of the two machines are different, but internally they are identical, sharing the same guts. Both the Adler 804 exhibited here, and the Miida MC840, along with the original machine from which the Miida and Adler machines were cloned, the Omron 800, share a design made by Japanese electronics company, Tateishi Electric, more commonly known as Omron. Omron stunned the calculator world in late 1971 by introducing the Omron 800, a basic four function, eight digit calculator, at a price that was roughly one-half that of competing calculators. All of the various incarnations of the Omron 800 share the exact same keyboard assembly, main electronics board, power supply module, and display module. The only differences are in cabinetry and keycaps.

The price reduction was made possible by Tateishi/Omron having their own integrated circuit fabrication facility. Omron was able to use these facilities to inexpensively produce a three device calculator chipset design licensed from Hitachi. With their own fabrication facilities, Omron was not at the mercy of integrated circuit suppliers, and had direct control over the manufacturing costs of the Large Scale IC's for their calculators. Many other calculator manufacturers were at the whim of the major calculator LSI chip manufacturers at the time, which were Rockwell, Texas Instruments, and Hitachi. Omron's introduction of a significantly less expensive machine than the price leader of the time, the Sharp QT-8D, threw the market for a loop, prompting Sharp and other calculator vendors to make price cuts in order to maintain a competitive position in the marketplace. Other calculator makers, such as Casio, Canon, and many of the other American and European calculator manufacturers were reliant on chips from either Texas Instruments or Hitachi, and were locked in to volume purchasing and price agreements with the chip makers, and had to cut margins substantially in order to remain competitive. Omron's chipset introduction, and the calculators based on this chipset, added more fuel to the fire in the shakeout of the calculator industry started by the QT-8D.

Adler is the brand name for a German office machine manufacturer, T-A Vertreibs-GmbH. Adler is mostly known in the US for their high quality typewriters. As with many office machine manufacturers, Adler was caught somewhat off-guard by the quick appearance of electronic calculators on the business machine scene. Rather than try to 'roll their own', Adler happened upon a business relationship with Omron, buying the guts for the calculator from Omron, and assembling their own version of Omron's 800 for sale into US and European markets. The Adler 804 exhibited here is a prime example of this relationship between Omron and Adler.

The Adler 804 is a very basic calculator with the four standard math functions, a constant for multiplication and division, floating decimal, and eight digits of capacity. While nothing really fancy in terms of capability, the 804 was priced right - $169 at its introduction, later reduced to $149. This price brought a basic electronic calculator into the realm of affordability for many small businesses, and even individuals for use in solving their day-to-day mathematical problems.

Closer View of Keyboard

The Adler 804 is an AC-only desktop calculator. It uses arithmetic entry, with "+=" and "-=" keys for addition/subtraction. Multiplication and division are performed as expected, with the "+=" key returning the results of either operation. A push-on/push-off "K" key locks in a constant multiplier or divisor. When the constant is activated, the "+=" and "-=" keys become inoperative. Only the multiply and divide keys perform any function when the constant function is active. The constant is entered on the keyboard, then the "K" key is depressed, then any number which to be multiplied or divided by the constant is entered, then the "X" or "÷" key pressed to calculate the result. This is a strange way to provide a constant function, not as usable as other implementations, but likely a design compromise as a result of packing all of the logic of the machine onto three chips. The "CA" (Clear All) key clears the entire machine, and the "CI" (Clear Indicator) key clears the display to allow for correction of incorrect entries.

The Vacuum Fluorescent Display Module

The calculator uses a vacuum fluorescent display panel of fairly unique construction. A metal enclosure wraps around the glass encapsulated display elements, and the electrical connections for the panel are brought out the back side of the enclosure by two arrays of wire pins. There are nine display elements in the panel, with eight of the elements containing the standard seven-segment and decimal point digit arrangement, and the ninth (right-most) position containing a sign and "10⁸" symbol which is used to indicate overflow.

Adler 804 Insides

The calculator is built upon a three chip calculator chipset made by Omron, but designed and used under license from Hitachi. The chipset has part numbers HD32104, HD32105, and HD32106. The HD32104 device appears mostly to be involved with keyboard scanning and encoding, and perhaps input register storage. The 32105 and 32106 devices appear to collaborate in calculation and display generation. The display panel is driven by a trio of Toshiba VF display driver chips, part number TM4352. The main board connects to the VF display panel via 14-pin IC-sockets on wire pigtails from the main board which plug into the wire pins on the back of the display panel, and connects to the keyboard assembly via a small (12-pin) edge connector.

Adler 840 Circuit Board (left), compared to Miida MC840 (Right) - Identical!

The 804 has full floating decimal, with the unusual distinction of having 'left to right' digit entry. The display provides leading and trailing zero suppression, always left-justifying all answers in the display. The calculator indicates overflow (either on input, or by calculation) by lighting the "10⁸" indicator, and locking the keyboard. The decimal point is positioned in overflow results such that shifting it eight digits to the right will result in an approximation of the answer, accurate to eight significant digits. For example, performing 12345679 X 63 results in 7.7777777, with the 10⁸ indicator lit. Shifting the decimal eight positions right results in 777777770, which is an approximation of the actual result of 777777777. Pressing the "CI" key clears an overflow condition, and leaves the result in the display for further calculation, if desired. Division by zero results in a zero answer (or negative 0 if the dividend was negative). While the "CA" key is depressed, the display is blanked. The 804 performs the "all nines" divided by 1 in about 1/3 second.