/fa/ - Fashion

Found a scan of a service bulletin for a rare transitional Timex model 62 movement. The model 62 was essentially a retrofitting of the model 4x series with a quartz timing package. The balance is impulsed by an electromagnet, and the timing of the electromagnet is controlled by an integrated circuit attached to a quartz crystal. This design was not very common, it was used only by a few manufacturers (Citizen and Luch come to mind).

The timex uses a very unusual quartz frequency of 49,152 Hz (as opposed to the much more common 32,768 Hz). The reason is obvious when you look at the frequency of the balance wheel (21,600bph, or 6 ticks per second). A series of 13 flip-flop circuits divides the frequency by 2^13, or 8192, which divides a 49,152Hz signal down to 6 pulses per second.

>>13700755
Timex had a very similar watch, the models 62 and 63. Based off the timex model 40, the quartz crystal ran at 49152Hz, a higher frequency than the standard 32KHz. This was divided down to 6Hz to run a 21,600 mechanical gear train. Watchmakers at the time would proudly advertise higher-frequency quartz crystals as improving accuracy. Like many early quartz watches (and unlike many modern quartz watches), the timex had a user-adjustable trimmer to adjust the rate of the quartz timing.

A pretty unusual design: 49khz quartz(!) controlling a 3hz electric balance.