COMPUCHRON HUGHES AIRCRAFT LED 1973
This is the first in the World LED watch by CompuChron from mid-1973. The not so sexy large goldplated case houses the first generation of Hughes Aircraft 29mm modules. You can clearly see below that this early module does not have a timing trimmer although the green plastic carrier already has been equipped with a cavity for this purpose. Hughes Aircraft was more than likely the only producer of LED modules that utilized a large high-frequency quartz oscillator 786.432Hz = 24 times higher than the market standard of 32.768Hz. They must have been convinced that a large frequency will deliver bullet-proof timekeeping without the need to adjust the rate. The aging process of quartz crystals and lack of temperature compensation proved them wrong and trimmers were added soon after before the end of 1973.
The dot-matrix display only shows time, date and seconds and AM/PM with an additional dot in the second left digit exactly identical as in the Bulova BigBlock from 1974. As shown Hughes modules had buttons already in early 1973 so it remains a mystery to me why Bulova used the akward and problematic stem-setting on their first LED instead of robust buttons. The circuitry for the first Hughes LED module was developed as early as 1972 as indicated on their inhouse microchips. There is no easy model name for these Hughes modules as this was a constant work in progress with new upgrades added at every step. In the collector world the modules are simply called 29mm from the diameter. Late modules were fitted with segment displays and such functions as leap year and day of week were added.
Keywords: compuchron, chronosonic led
Market value: 25-100$ (model, condition, box)