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Commodore US*8 Desktop Calculator

Updated 6/1/2020

This old calculator was found at a Goodwill Industries thrift store in Portland, Oregon in 1992, for $2.00. Other than cleaning some grime off the cabinet and keyboard, and blowing the dust out of the inside of the calculator, it looks and works great, which is somewhat surprising for a buget-minded lower-end personal desktop calculator.

This calculator, based on the date code on the single Large-Scle Integration(LSI) device inside, was likely manufactured in the early part of 1973. It is a desk-top style calculator, using AC line power. It utilizes a single Texas Instruments chip, the TMS0103NC, which is one of TI's first-generation of single-chip calculator IC's, for its calculating brains. Along with the TI chip, an assortment of plastic-packaged transistors and discrete components for power supply and display driving functions. The US*8 is one of the earliest electronic calculators to be actually manufactured by Commodore, with earlier machines made by other companies (such as Casio in Japan) and sold under the Commodore brand under OEM contracts. Commodore cranked out these calculators by the thousands, distributing them to department and discount stores such as JC Penney, KMart, White Front, Sears & Roebuck, Korvettes, and Fred Meyer among many others.

The Commodore US*8 minus its cabinet
Note the unusual diagonal mounting of the Texas Instruments LSI chip

The display is a Burroughs Panaplex-style planar gas-discharge display, with standard seven-segment digit arrangement. The display panel has 9 digits, but the left-most digit is used only for sign (-) and error/overflow(E) indication.

The planar gas-discharge display in operation

The US*8 is very typical in its operation, with adding-machine style [+=] and [-=] keys for calculating sums and differences, along with [X] and [÷] keys, with the [+=] key used for completing calculation of products or quotients. A slide switch on the keyboard panel selects several fixed decimal point locations, or automatic floating decimal mode.

The Hugle International Hugle-8 Calculator

There is another calculator that could easily be mistaken as a copy of the Commodore US*8. The Hugle-8, produced by Hugle International of Mountain View, California, looks virtually identical to the Commodore US*8, with the only notable visual difference being that the Hugle-8 is missing the decimal point selection slide switch above the math function keys. The reason the switch is missing is that the Hugle-8 always operates in automatic floating decimal mode. The reason? The Hugle-8 uses completely different LSI calculator-on-a-chip, the Nortec 4204, designed by the relatively short-lived large-scale integrated circuit design house, Nortec Electronics(1966-1972). Nortec designed the logic and layout of the 4204 IC, and had it fabricated by American Micro-systems, Inc. (AMI), although the chip has only the Nortec name on it. Nortec was founded by Large-Scale Integrated Circuit design pioneer Robert Norman[3/24/1927-1/21/2017] in October of 1966, had its roots in General Micro-electronics (GMe). GMe made its place in history by developing the first Metal Oxide Semiconductor (MOS) Large Scale Integration calculator chipset used in the remarkable Victor 3900 electronic calculator introduced in 1965. It isn't clear if there was a relationship was between Commodore and Hugle International, though it seems likely that there was some sort of agreement between the companies. A large Hugle International logo appears in the location where the decimal point selection slide switch would be on the US*8 cabinet. It seems plausible that the cabinet and keyboard assembly was purchased by Hugle International from Commodore, and Hugle placed the logo block-off plate over the hole for the decimal point switch on the US*8 cabinet, applied their own badging, and used their own power supply and calculator electronics inside the cabinet. If you happen to have a Hugle International Hugle-8 calculator, please contact the museum by clicking the EMail link at the top of this page. The museum would be interested in acquiring one of these calculators, preferably in working condition, but if you have one that isn't working, we'd still like to hear from you.

Commodore was a significant player in the mass-market electronic calculator realm, being one of the first to market low-cost calculators for use in homes as well business. Commodore initially got into the electronic calculator marketplace around 1967, when it forged an agreement with Casio in Japan to import Casio-made electronic calculators into Canada, and market, distribute, and support them in North America under the Commodore brand name. An example of a calculator made by Casio and sold under the Commodore brand is the Commodore 500E, which is identical to Casio's 101E, which is the export version of Casio's third electronic calculator, the Casio 101.

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