Introduced in 1987, Calibre 630 was the first member in the Jaeger-LeCoultre Mechaquartz family. It was a complicated movement, with 25 jewels. At the time, it was advertised as a revolutionary thin chronograph, measuring just 23.30 mm diameter and 3.70 mm thick. This made it 1/3 the volume of most contemporary chronograph movements and 40% smaller than the smallest equivalent movement on the market.
There are two motors in the calibre
Since the chronograph is mechanical, it has the same feel as a conventional chronograph movement, including mechanical zero reset. Yet the Mechaquartz was much more compact than a conventional automatic chronograph movement.
Calibre 630 differed from Calibre 631 in that it included a moon phase indicator.
Note There is conflicting information on the quartz frequency, with some sources claiming dual 1 KHz and 4 KHz crystals and others claiming 32 KHz. It is likely this confusion comes from the 1 and 4 Hz motors.
Calibre 630 was used in chronograph watches in the 1980's and 1990's, though not as widely as Calibre 631