OPERATING INSTRUCTIONS
GENERAL RECOMMENDATIONS
A YEMA watch correctly used and cared for will serve you reliably for years provided that the following precautions are carefully followed.
AVOID MAGNETIC FIELDS
Avoid contact with magnets, or putting your watch on top of loudspeakers, refrigerators or smartphones, since such objects generate magnetic fields which could disturb the regulating organs of your watch.
SWIMMING IN THE SEA
Always rinse your watch with fresh water after swimming in the sea.
AVOID SHOCKS
Avoid to expose your watch to violent and/or sudden physical or thermal shocks, like playing tennis, golfing, mountain biking, sauna, etc.
CROWN ESSENTIALS
Always ensure that the crown is screwed back in completely to prevent water from entering the mechanism. Never operate the crown under water.
EXTREME TEMPERATURES
Avoid exposure to extreme temperatures (greater than 60°C / 140°F, less than 0°C / 32°F) as well as extreme temperature changes.
AVOID CHEMICALS
Avoid direct contact with solvents, detergents, perfumes, cosmetics, insect repellents, etc. since they may damage the bracelet, case or gaskets.
CROWN POSITIONS
The crown is a high precision part. Your watch is equipped with either a push/pull or a screw-down crown, it is fitted with seals to prevent any water penetration. Your watch is waterproof only if the crown is pushed or screwed down all the way.
The crown has 3 positions :
0 : Pushed or screwed down position
1 : Winding position
2 : Time setting position
WINDING YOUR WATCH
The CMM.20 is an automatic caliber that charges with the rotation of a small oscillating weight made of tungsten, also called micro-rotor, integrated into the movement and which freely rotates following the movement of your wrist.
If you haven't worn your watch for more than 70 hours, it will stop. In this case, you must manually wind it.
As a general rule we recommend to favour automatic winding and only use manual winding to restart a watch.
AUTOMATIC WINDING
If your watch is running and is regularly worn during at least 8 hours a day, it does not require manual winding.
MANUAL WINDING (RECOMMENDED PROCEDURE)
We recommend to restart your watch by fully turning the crown just a dozen times, then immediately wear it. After wearing your watch for two consecutive days, it should fully recharge automatically.
To do so, unscrew the crown anti-clockwise (if applicable, pull the crown) until you reach the winding position (1) then turn the crown clockwise a dozen times.
Then push the crown back in to the locked position (0). For screw-down crowns make sure you screw it down all the way.
MANUAL WINDING (OPTIONAL PROCEDURE)
This method is rather recommended for mechanical calibers not having an oscillating weight but it works as well for your CMM.20 automatic caliber. Provided that your watch is not running you can fully wind the mainspring by turning the crown clockwise 50 times.
ADDITIONAL NOTES
Please note that the CMM.20 average observed power reserve is 70h (+/-10%).
TIME SETTING (HOUR AND MINUTES)
Unscrew the crown (if applicable, pull the crown) and pull it out all the way to the time setting position (2).
Turn the crown in either direction until the hour and minute hands indicate the desired time.
Then push the crown back in to the locked position (0). For screw-down crowns make sure you screw it down all the way.
ADDITIONAL NOTES
When setting the time, the central seconds hand might make slight jumps clockwise and/or anti-clockwise. This is expected behaviour by design caused by gear train backslash (clearance between mated gear teeth).
TIME SETTING (SECONDS)
You can set the seconds hand provided that your watch is wound down.
Unscrew the crown (if applicable, pull the crown) to reach the winding position (1).
Begin to wind the watch when the actual time matches the time of the seconds hands of your unwound watch. If for example your seconds hand has stopped at 15, wait until the actual time indicates 15 seconds, then start winding your watch, which will start the seconds hand.
Now your watch is wound and your seconds hand is synchronised with the actual time, set the hour and minutes hands following the instructions in above section.
ACCURACY
The CMM.20 is calibrated to achieve a near chronometric precision of -3/+7 seconds/day.
The caliber's maximum variation is -5/+10 seconds/day. Beyond this tolerance your caliber might require servicing.
MOVEMENT COMPONENTS
All CMM.20 caliber components are manufactured in France and Switzerland within a range of 72km from Morteau by recognized craftsman in fine watchmaking. The caliber bridges and mainplates are manufactured in YEMA’s workshops in Morteau where final assembly of all components takes place.
COMPONENTS
ORIGINS
Movement Design
Switzerland
Movement Components
France + Switzerland
Assemblies
France