JLC 633

Calibre 633 was a quartz watch movement with a mechanical chronograph developed by Jaeger-LeCoultre and also used by IWC.

Calibre 633 was a member of the Jaeger-LeCoultre Mechaquartz family. It was the most complicated movement in the family, with 27 jewels and an alarm function.

There are two motors in the calibre:

• One powers the main timekeeping hands at a frequency of 1 Hz
• A second powers the mechanical chronograph at 4 Hz

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 633 differed from Calibre 630 and 631 in that it included an alarm function.

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.

Applications

Calibre 633 was used in chronograph watches in the 1980's and 1990's, though not as widely as Calibre 631:

• Jaeger-LeCoultre Heraion Chronograph Reveil
• IWC Ingenieur Chronograph Alarm

External Links

• Mechaquartz Chronographs

Manufacturer: Jaeger-LeCoultre Description: Quartz movement with mechanical chronograph Functions: Hour, minute hands Small seconds at 6:00 Alarm Chronograph with 30 minute and 12 hour subdials at 9:00 and 3:00, respectively Data: H 3.8 mm D 23.3 mm 27 jewels Frequency 32 KHz Production period: 1980's