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Adler 804 Electronic Calculator

Updated 4/29/2009

The Adler 804 is very similar in function to another calculator in the museum, the Miida MC840. The cabinet and general style of the two machines quite 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 calculators originated, 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 same keyboard assembly(with different colored key-caps), main electronics board, power supply module, and display module. The only differences are in cabinetry design, colors, and key caps.

The price reduction was made possible by Omron contracting with a new player in the field of Large Scale MOS (MOS/LSI) 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 chip set had its genesis in 1963, at a new company called General Micro-electronics (GM-e). Some time in late 1963 to early 1964, one of GM-e's engineers had built a simple four function, eight digit electronic calculator using GM-e's small-scale bipolar IC family that was called "Milliwatt Logic". The engineer that built the calculator thought (insightfully) that there could be a huge market for a relatively small, (compared to the noisy electromechanical desktop behemoths like the Friden STW-10) silent all electronic calculator. At the time, electronic calculators were in their infancy, and were typically made using discrete transistors, which meant they took quite a bit of space, used quite a bit of power, and generated a bit of heat due to the hundreds of transistors required to make a calculator. The machine that this engineer had made used tiny integrated circuits for its logic, which meant it could be built smaller, use significantly less electricity, and would generate very little heat. Efforts were made to convince GM-e management to start a project to turn the calculator into a production product, but it was sidelined after management decided that going into the calculator business would dilute its focus on manufacturing integrated circuits, and the idea was dropped.

GM-e had a short but illustrious history, including the development of the miraculous Victor 3900 all MOS/LSI integrated circuit calculator in 1965 (about four years ahead of its time), but the project to develop the calculator for Victor Comptometer ended up putting the company into debt that it was proving very difficult to repay, so General Micro-electronics was sold to Philco-Ford Electronics in early 1966. Many of the players at GM-e left to start up new companies, or join existing semiconductor manufacturers.

Nortec Electronics was one of the spinoffs of GM-e, founded by one of the original founders of General Micro-electronics, Robert Norman. Fairly early in Nortec Electronics' history, Omron contracted with Nortec to design, lay-out, and manufacture a calculator chip set for Omron. Omron intended to put the chip set into a small, low-cost, basic electronic calculator, which they put on the market as the Omron 800. Along with marketing the Omron 800, Omron also would sell complete calculators, or the main circuit board containing the chip set to anyone who was willing to buy them in wholesale quantities at reduced price depending on how many the customer would commit to purchase over a given period of time. The Omron 800 calculator hit the market in May, 1971 at a retail price of $179, for its capability at the time, was the deal of the century, as comparable electronic calculators were typically selling for around $395. The calculator began selling lot hotcakes, causing a bit of a panic among competitors in the calculator marketplace. competitive.

The calculator design that was built as an employee project at GM-e ended up being used as the basis for the logic of the Nortec three IC calculator chip set used in the Omron 800, was designated the ALPHA chip set. Since the logic design done at GM-e was tried and true, and the engineer who developed it used the calculator he'd build every day for his work, it was just a matter doing some basic tweaking of the logic, and then 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 chip sets on the market at the time.

Due to an unfortunate tactical error by Nortec, the price of the chips to Omron was inadvertently increased by a small amount. While the price increase was an error, in the end, it led to Omron canceling their contract with Nortec, giving the design (which Omron owned as part of the contract) to Japan's 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 at the time, the Sharp QT-8D, surprised the calculator market, throwing it for a loop. Omron's move forced Sharp and many other calculator makers to make fairly drastic 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 finished calculators with Adler's desired color scheme from Omron, with Adler branding and serial number tags attached by Adler, and then placing the 804 for sale into US and European markets. Adler wasn't really in competition with Omron, because Omron sold primarily into the Orient, but it had established a US operation, and that operation got its start by coordinating the formation of the relationship with Nortec. It took a little time before the US operation had set up its distribution network in the US to sell Omron calculators, but and though Adler did sell the Adler 804 in the US, its primary market was in Europe.

The Adler 804 is identical in function to the Omron 800. It is a 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 introduction, and not long after, reduced to $149. The original price was a bit more than the suggested price of the Omron 800, but given that the Omron 800 wasn't yet available in the US, Adler felt it could justify a bit higher price. Even at the slightly higher price, the Adler 804 brought a basic electronic calculator into the realm of affordability for many small businesses, and even for 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 Adler 804 uses a vacuum fluorescent display module 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 stiff wire pins. There are nine display positions in the panel, with eight of the elements containing the standard seven-segment and right-hand decimal point digit arrangement, and the ninth (right-most) position containing a negative sign and "108" symbol which is used to indicate overflow.

Adler 804 Insides

The Adler 804 is based on the Hitachi-made version of the ALPHA chip set. The exhibited example of the 804 was build after the manufacture of the chip set had been turned over to Hitachi by Omron. 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 chip set 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 HD32105 and HD32106 devices appear to collaborate in calculation and display generation. The display module is driven by a trio of Toshiba VF display driver chips, part number TM4352. The main board connects to the VF display module via 14-pin IC-sockets on wire pigtails from the main board that plug into the wire pins on the back of the display module. The main board connects to the keyboard assembly via a 12-pin edge connector.

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

The 804 has automatic floating decimal point placement, 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 ignoring key-presses on the keyboard until the [C] or [CI] key is pressed. 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 ©1997-2023, Rick Bensene.