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Adler 804 Electronic Calculator

Updated 4/29/2009

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. 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 facilitated by Japanese electronics company, Omron Tateisi Electric Co., 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 clones 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 design, colors, and keycaps.

The price reduction was made possible by Omron contracting with a new player in the field of Large Scale MOS integrated circuitry, Nortec Electronics. The story is somewhat convoluted, but the beginnings of the logic design that was used to make the three chip calculator had its genesis in 1963, at a new company called General Micro-electronics (GM-e). One of GM-e's employees had built a simple four function, eight digit electronic calculator using GM-e's small-scale bipolar IC family that was called Milliwatt Logic. For a short time, GM-e contemplated turning the calculator into a production product, but it was sidelined after management decided to stick with its bread and butter business, which was making MOS IC's. GM-e had a short but illustrious history, including the development of the amazing Victor 3900 calculator, but that ended with the company being sold to Philco-Ford Electronics in early 1966. Many of the players at GM-e left to start up new, or join existing semiconductor manufacturers. Nortec Electronics was one of the spinoffs of GM-e. Omron contracted with Nortec to develop and manufacture a calculator chipset for Omron to use in their calculator, as well as for Omron to sell to other manufacturers. The calculator design that was built at GM-e ended up being used as the basis for the logic of the Nortec three IC calculator chipset, which was designated the ALPHA chipset. Since the logic design done at GM-e was tried and true, it was just a matter of translating the logic into MOS integrated circuit layouts. Given that MOS IC technology had come a long way since the days of GM-e, the chip design was quite simple and easy to fabricate, making it possible to price the chips such that they were significantly cheaper than any other calculator-related chipsets on the market at the time. Unfortunately, a tactical error by Nortec, who increased its price of the chips to Omron, resulted in Omron cancelling their contract, and giving the design (which Omron owned as part of the contract) to Hitachi, who then fabricated the chips at an even lower price than Nortec was originally pricing them. Omron's introduction of the 800 calculator, a significantly less expensive machine than the price leader of the time, the Sharp QT-8D, threw the market for a loop, forcing Sharp and many other calculator vendors to make price cuts in order to maintain a competitive position in the marketplace.

Adler is the brand name for a German office machine manufacturer, Triumph-Adler 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 formed a business relationship with Omron, buying the guts for the calculator from Omron, and assembling their own version of the machine for sale into US and European markets.

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 powered 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 an unusual way to provide a constant function, not as usable as other implementations, but likely a design characteristic that carried over from the original calculator designed at GM-e. 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 designed and manufactured by Hitachi. Omron's agreement with Hitachi stated that the chips would have Omron's name on them, with no indication of Hitachi, though the part-numbers on the chips carry Hitachi's "HD" prefix which is a pretty good give-away. 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) - Virtually 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 the 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.


Text and images Copyright ©1997-2016, Rick Bensene.