Jaeger-LeCoultre Caliber 819 – Technical Overview from Document 1138_JLC

The Jaeger-LeCoultre Caliber 819 is a manual-winding mechanical alarm movement developed as part of the Memovox family in the 1960s and 1970s. Document 1138_JLC provides a complete technical breakdown of the movement, focusing on its dual-barrel architecture, alarm functionality, and clean timekeeping design. Unlike its automatic sibling calibers (e.g., Cal. 815 and 825), the 819 is manually wound for both the timekeeping and alarm barrels, resulting in a thinner profile and simpler servicing.

Technical Specifications

• Type: Manual-winding

• Functions: Hours, minutes, central seconds, mechanical alarm

• Jewels: 17

• Frequency: 21,600 vibrations per hour (3 Hz)

• Power Reserve:

  • Timekeeping barrel: ~42–45 hours

  • Alarm barrel: ~18–20 hours

• Diameter: ~28.0 mm

• Height: ~5.8 mm

This caliber features the hallmark dual-barrel system, with one barrel driving the timekeeping gear train and the other dedicated exclusively to the alarm mechanism.

Key Features from Document 1138_JLC

Document 1138_JLC illustrates the movement layout and servicing procedures in a clear, schematic style. Important structural elements include:

1. Dual Barrel System

• Main barrel: Wound via the primary crown, drives timekeeping

• Alarm barrel: Wound via the second crown, powers the mechanical chime

2. Alarm Mechanism

• Alarm disc: Rotates beneath the dial and is set via the secondary crown

• Trigger lever and cam: Releases the hammer when the preset time is reached

• Alarm hammer: Strikes a pin or resonance plate inside the case to produce the audible sound

3. Manual Keyless Works

• Single-level manual winding system for both barrels, with separate gear trains and winding paths

• Sliding pinion and clutch designed for efficient transition between winding and setting modes

Watchmaker Notes

Document 1138_JLC includes practical service notes:

• Lubrication: Light oil on pivots of time train and alarm train; no lubrication on the alarm hammer pivot to preserve sound clarity

• Alarm testing: Check the hammer swing amplitude and confirm resonance using the case back

• Trigger system: Must be aligned carefully during assembly to ensure reliable alarm release at the exact time

• Crown settings: Confirm that each crown winds the correct barrel and sets the appropriate function (time or alarm)

Applications

Caliber 819 was used in:

• Manual-wind Memovox models, primarily from the late 1960s and early 1970s

• Watches with dual-crown layout (one for time, one for alarm)

• Typically in 36 mm steel or gold cases, with classical dial designs featuring inner alarm-setting discs

These watches offered the utility of a mechanical alarm with the purity of manual-wind operation.

Conclusion

The Jaeger-LeCoultre Caliber 819, as detailed in document 1138_JLC, is a manually wound alternative within the Memovox alarm family, offering a slimmer and more mechanically straightforward movement compared to its automatic counterparts. Its dual-barrel architecture ensures separation of power between timekeeping and alarm functions, while its robust layout provides ease of servicing and long-term reliability. For watchmakers and collectors alike, the 819 remains a practical and collectible piece of mechanical innovation from Jaeger-LeCoultre’s golden era.