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Fairchild LCD Tritium Mod

Nuclear power on your wrist!


This is a modification of the Fairchild LCD Digital Watch described here. This model featured a backlight powered by radioactive Tritium. Unfortunately, Tritium has a half-life of only 12.3 years. Even nuclear power isn't unlimted. As a result, after nearly 40 years, the Tritium has lost much of its glowing power. What to do? Thanks to the wonders of the Internet, it was possible to buy replacement Tritium to make the watch glow as well (or better) than new!

Tritium is an isotope of hydrogen where the nucleus contains a single proton like normal hydrogen plus two extra neutrons. Since Tritium is an isotope of hydrogen, it is in gaseous form at room temperature and must be contained by glass vials. The Tritium itself doesn't actually glow but emits beta radiation (electrons) which can be used to cause a phosphorto glow just like the CRTtubes in old fashioned television sets (anyone remember those?) Unfortunately, in addition to its pretty glow, Tritium is also useful if you happen to have a fission bomb and would like to boost the yield. As a result, it is restricted by the U.S. government and is therefore not the easiest substance to acquire. :-)

A Tritium Atom

Replacing the Tritium vials in the watch is quite easy. As can be seen in the photos, the Tritium is stored in two rectangular vials which are kept in a little white tray in a space behind the LCD. For this watch, I replaced the two rectangular green glowing vials with a set of 10 new cylindrical 5x1.5mm Tritium vials that glow in the various colors of the spectrum. The color of the glow is determined by the type of phosphor coating the inside of the vials. The Tritium in each vials is identical. Unfortunately, Tritium is rather expensive and these tiny grain of rice sized vials cost about $60 or about $6 each. The result is a pleasing colorful glow slightly dimmer than glow sticks but glowing continuously and making it quite easy to read the watch in the dark.


This watch is in 100% NOS mint condition original condition with the exception of the newly replaced Tritium vials!

Case: Excellent.
NOS, close to mint.

Face / Hands: Excellent.
NOS, mint.

Crystal: Excellent.
NOS, mint.

Band / Bracelet: Excellent.
NOS, mint.

Function / Accuracy: Excellent.
All functions work properly. Digital quartz accuracy.