The standard ground screw is replaced by a longer gold-plated one which has a tip that projects through the other side of the pillar plate and insulated from it. Thus the screw is now isolated electrically from the pillar plate. This version still has the standard component coil assy, however, the pillar plate hole which receives the ground-plate screw has been replaced by an insulated bush. When the crown is pushed back in, the pawl finger re-engages the index wheel, which begins to turn again. The electronics continue to function as per normal and the fork keeps humming. When the watch crown is pulled out, a small pin attached to a lever (the Hack Lever) lifts the pawl finger slightly off the index wheel, stopping the watch. The ground plate on these models has a permanent electrical connection to the pillar plate by a screw, which also acts as a mounting screw. The ground plate is indicated by an arrow, because changes were made to this in other 218's. The pics above shows the component coil assy for a standard 218 (ie 2180, 218D, 2181, 2182). Below is a standard 218, made in the USA. The "hack" mechanism is the device which stops the watch when the crown is pulled out for time-setting. There are two variations from the original 218 to the electronics and "hack" mechanism. depending on what they could get at the time. This is to allow for different types of transistors to be used. They have changed they way the feedback is applied to the transistor, and have made provision for a resistor in series with the transistor "base" pin. The 218 electronics are very similar to the 214. A couple of very collectible versions are the "Astronaut" I and II, on which it is possible to change the hour-hand indication without disturbing the time displayed.įor a description of the 218 gear train, and a comparison to the 224 train, click here Many of the versions of this calibre are seen as variations of the date and day function. Just looking at the list of derived calibres above shows that Bulova really got everything right with this design. It can be found with a great variety of case styles and dials. It is an excellent movement, both for its functionality and also relative ease of repair (by watch-repair standards that is). The Accutron 218 would probably be the most common type you will find.
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