====== JLC 631 ======
**Calibre 631** was a [[quartz]] watch movement with a mechanical [[chronograph]] developed by [[Jaeger-LeCoultre]] and also used by [[IWC]].

Introduced in [[1987]], Calibre 631 was the second member in the [[Jaeger-LeCoultre Mechaquartz]] family after [[JLC 630|Calibre 630]]. It was a complicated movement, with 25 jewels and 233 components.

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.

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 631 was widely used in chronograph watches in the 1980's and 1990's.

  * [[Jaeger-LeCoultre Heraion Chronograph]]
  * [[Jaeger-LeCoultre Kyros Chronograph]]
  * [[Jaeger-LeCoultre Odysseus Chronograph]]
  * [[Jaeger-LeCoultre Master Chronograph]]
  * [[IWC Porsche Design Sportivo 02 Chronograph]]
  * [[IWC Porsche Design Titan Chronograph]]
  * [[IWC Ref. 3739]]
  * [[IWC Ingenieur Chronograph]]
  * [[IWC Portofino Chronograph]]
  * [[IWC Ladies Portofino Chronograph]]
  * [[IWC Flieger Chronograph]]
  * [[IWC SL Chronograph]]
  * [[IWC GST Chronograph]]
  * [[Chopard Happy Sport Chronograph]]

===== External Links =====
  * [[http://www.qahill.com/tz/mq/mq.html|Mechaquartz Chronographs]]


<WRAP ud ud_mov>

**Manufacturer:**
  * [[Jaeger-LeCoultre]]

**Description:**
  * [[Quartz]] movement with mechanical [[chronograph]]

**Functions:**
  * Hour, minute hands
  * Small seconds at 6 00
  * Chronograph with 30 minute and 12 hour subdials at 9 00 and 3 00, respectively

**Data:**
  * H 3.8 mm
  * D 23.3 mm
  * 25 jewels
  * 233 components
  * Frequency 32 KHz

**Production period:**
  * [[1987]]-
</WRAP>

{{tag>Movements Quartz_movements Jaeger-LeCoultre_calibres Jaeger-LeCoultre_quartz_calibres Jaeger-LeCoultre_Mechaquartz_calibres}}