After the initial batch of DSM watches that were produced for approximately 6-12 months Optel in late 1973 introduced the next ("second") generation of watches with a robust and power-efficient Field Effect display. Most of these (up to approx. serial number 35.000) are practically identical with the earlier DSM circuitry with 5424 chips that were simply refitted with FE displays. Many of these will work with either DSM or FE displays however the power supply components tend to age unevenly so this is a trial and error game. Later versions from 1974 had modified boards and components including a 5202 microchip and will only work with FE displays. Optel square watches with FE can be found with many brands including factory refitted "Optcom I's" however the most popular was the Segtronic made especially for American Express.



AMEX offered the Segtronic for an unbeatable bulk price of 119$ to their loyal customers for a Free Trial. It was available in stainless steel and what is surprising... 18K electroplated ...all stainless steel cases! Remarkable quality for an affordable  price IMO. The goldplated versions of Optel watches should have a gold display to match the case and the steel versions a silver color but you can easily modify this if necessary. The display color is a result of a metallic  sticker applied to the background of the glass display so that the digits are visible for the wearer. Any kind of reflecting sticker or film can be applied to match personal preferences. Many displays are damaged due to extensive pressure or improper handling. To minimize the risk of broken corners I suggest to apply the polarizing filter on top of the frame as pictured right.

Without the filter underneath there will be slightly less pressure from the display frame so you might need to adjust the display springs/pins to connect all segments properly. This is a lot safer then to slide the frame by force together with the filter. The gap between the plexi crystal and display frame usually does not exceed 1mm so make sure that the crystal is fitted properly in the case as it might produce additional pressure on the display frame and smash it when the snap-fit case is closed. Additionally a large square rubber gasket should be present on the inside of the case that also acts like a spacer preventing the case to be snap-fitted to firmly. A missing gasket/spacer can be replaced with small pieces of rubber/insulating tape in the four corners as long as the rubber is soft with a thickness of approx. 1-2mm's.


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Keywords: segtronic, lcd, field effect, optel

Market value: 100-350$ (version, condition, box)

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