Uranus was a pioneer in the LED watch industry with inhouse circuits and watches already sold in 1972. This 1975 calculator is their most advanced concept and also the smartest user-friendly design applied to digital watch calculators in those days. I wonder if Uranus was marketed as top-shelf because the outer quality  of this watch is unfortunately not even close to that of Pulsar or HP-01. The materials used place it closer to the Hughes/CompuChron calculator. The case is chrome-plated, the crystal is plastic and the bracelet is generic fitted to many no-name watches without even an Uranus emblem on the clasp. Despite these flaws the low production volumes and cool design with smart keypad have made the Uranus one of the most collectible LED watches in history.



The "Made in USA" screw-back reveals the module which also proves to be a disappointment at first glance. The fibreglass carrier is extremely cheap with battery springs and quartz crystal simply press-fitted into metal tubes without any soldering. They can be pulled out quickly to disassemble the circuit board from the black carrier. The circuitry is weird and looks like if it was assembled in a garage :) A wire protrudes from beneath from the button contact at 9 o'clock and connects to the single diode affixed to the green area on the front where some models contain a solar-charge panel. Only one segment from this diode is wirebonded to the substrate and very likely lights up when the watch is connected to mains for a battery charge. Some models had a special horse-shoe charger which was screwed onto the buttons at 3 and 9.



Removing the circuitr board from the plastic carrier requires extreme care and the button contact at 9 o'clock must be removed together with the substrate. The bottom side reveals a maze of chips and a hundred wirebonds. Susprisingly the twop main microchips are not of Uranus origin but were made by Exetron and Toshiba which also provided components to the Pulsar Calculator. I guess that after 1975 American companies stopped inhouse IC development and simply outsourced everything possible. One of the chips is marked 08-01-1975 which very likely stands for August and not January 1975.  This date proves that a wrist calculator was not just a Pulsar idea and that such concepts were implemented in parallel by a few companies in those days prior to the launch of the Pulsar Calculator at the end of 1975.



As there is nothing more to analyze simply enjoy the 200x magnified close-ups of the Uranus circuits. I always wanted to have this watch but the delicate construction tells me to stay away. This Uranus was sent to me for repairs with at least 15 broken wirebonds that were caused by extreme shock. This amount of bonds might be repaired with silver epoxy after hours and hours of work but I'd suggest to acquire a $10.000 wirebonding machine that will make such bonds durable :) If you like surprises and taking risks then the Uranus Calculator is a watch for you!


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Keywords: uranus calculator, uranus led

Market value: 500-1800$ (goldplate, chromeplate or anodized black, condition, box, papers)

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