Movement record · Switzerland

Valjoux/ETA 7750 family

Partially verified

Cam-switched automatic chronograph with an oscillating pinion

Technical specifications

Diameter: 30.0 mm
Height: 7.9 mm
Jewels: 25 (variants differ)
Frequency: 28,800 vph (4 Hz)
Power reserve: Approx. 44 hours
Winding: Automatic with manual winding
Setting: Pendant set with quick-set date
Escapement: Swiss lever
Balance: Monometallic balance with alloy hairspring
Complications: Chronograph, Date, day-date in variants

Identification features

Cam-and-lever chronograph switching rather than a column wheel
Characteristic three-register layout in the standard version

Known variants

Two-register and single-register derivatives
Day-date and moonphase variants

Servicing notes

Cleaning, lubrication, mainspring and pivot work belong with a qualified watchmaker working from calibre-specific documentation. Conserve original parts: replacing a worn component with a modern substitute changes the object, and refinishing plates or dials destroys evidence.

General guidance only. Antique movements should be serviced by a qualified watchmaker.

Historical significance

The calibre that made automatic mechanical chronographs affordable and kept them in production through and after the quartz era.

Diagram

Schematic: plate and bridge layout. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

de Carle, D., Watch and Clock Encyclopedia
Period trade material catalogues and calibre reference compilations (edition-dependent)
Published manufacturer technical documentation where available

Where sources disagree, the disagreement is stated rather than resolved silently.