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Valjoux 7750 series                                           do not change the date between the hours of 7pm and 3am

Before the arrival of the first chronograph modules which could be mounted onto existing automatic calibers, the economically designed and produced Valjoux 7750 remained the most reasonably priced Swiss-Made automatic chronograph movement. It also helped that it wasn't subject to any sales restrictions anywhere.

The Valjoux 7750 is available direct from the factory with three enhanced finishes in addition to the standard finish: "Elaboré," "Top" and "Chronomètre." A separate department handles special customer requests. The company offers different versions of its chronographs with date (7750 and 7760 with manual winding), the chronographs with full calendar and moon phase (7751 and 7761 with manual winding) as well as the lesser-known automatic chronographs with moon phase (7758) and the manual-wind chronograph without the 12-hour counter (7765). No wonder so many small and large ateliers are falling over themselves to develop additional versions of the popular and durable "motor." The amazing diversity of 7750 versions surprised even us. And although we make no claim of proving a complete list here, the following pages illustrate the most common types of Valjoux 7750s.

The Valjoux 7750[21] a/k/a ETA 7750 is a widely used chronograph (stop watch) movement operated by cams integrated into the movement. The traditional mechanism used in the chronograph is known as the Column Wheel. With the advent of the Valjoux 7750, the column wheel was abandoned for a three plane cam system. The three plane cam system is properly known as the Coulisse Levier mechanism. The system and movement were developed by Edmond Capt in 1970, as a fully integrated self-winding mechanism with quick-set day/date based on the Valjoux 7733.[22]

The movement is an automatic winding, 17 Jewels (early models), some say more collectable, then 25 jewel movement, both can be fitted with a variety of features including the triple date (day, date, month and moon phase) or a variety of two and three register models with totalisers or counters for minutes, seconds and hours. It is available in three executions or grades: Elaborated, Top and Chronometer. The key components which differ at the line of demarcation between Elaborated and Top are the pallet stones, balance wheel & hairspring and the regulator mechanism. To illustrate the differences in accuracy garnered by the successive grades, consider the following specifications:

The Elaborated grade is adjusted in three positions with an average rate of +/−5 seconds/day with a maximum daily variation of +/−15 seconds/day, some have beautiful engravings, and may have coloured parts also normally produced by the watchmaker.

The Top grade is adjusted in five positions with an average rate of +/−4 seconds/day with a maximum daily variation of +/−15 seconds/day, some have beautiful engravings, and may have coloured parts also normally produced by the watchmaker.

The Chronometer grade must meet strict standards prescribed by the COSC: an average rate of −4/+6 with a maximum daily variation of +/−5 seconds/day, some have beautiful engravings, and may have coloured parts also normally produced by the watchmaker with signature.

Whichever you are fortunate enough to own all are described as the most reliable of chronometres.

Valjoux ETA 7750 automatic chronograph movement care and use.

To set time: Unscrew or pull out crown and pull crown out to position 3. Turn crown clockwise to correct time. Push in crown into position 1 and turn counterclockwise until the threads click on the stem tube than proceed to screw down the crown.

To set day and date: Pull crown out to position 2. Turn crown clockwise to advance date.

Turn crown counter clockwise to advance day.

Push crown into position 1 for normal position and push in or screw down.

To activate chronograph: Push button A to start and stop. Push button B to reset only after a full stop. A full rotation of chrono-second accumulates to one chrono-minute. A full rotation of chrono-minute accumulates to 30 minutes. A full rotation of the chrono-hours accumulated to 12 hours. Do not activate the chronograph function underwater.

Care and maintenance: Automatic movement can be wound by crown or rotor. To restart an automatic after a period of not wearing, it is best to manually wind it with approximately 30 turns clockwise by first unscrewing the crown, once the crown is released to position 1 proceed to wind the mainspring. To use the rotor method for winding, turn watch counter clockwise with watch dial facing you. The rotor will also turn counter clockwise. Rotor turns 800 times per day.

Important fact: Operation of the quick set must executed slowly and carefully. Do not operate the quick set day and date change during the slow date change engagement time frame between the hours of 7PM to 3AM. Doing so will damage the movements date driving wheels, intermediate setting wheel and double corrector. In order to repair this the date platform and setting bridge will need to be disassembled and the damaged parts replaced. This is not covered under warranty.

Cases with screw down crowns: Please be mindful not to over tighten the crown as the internal seals will protect the case from moisture exposure. Over tightening the crown can produce premature wear to the crown threads and compromise the stem tube seal.