Why is my Stem not working in an ETA 2824 or similar movements?
One question that comes up on a regular basis is when someone has taken the winding stem out of a watch movement and cannot get it locked back in or get it to work properly through the different crown positions. In some cases, the stem has just fallen out and there seems to be nothing you can do to make it stay in and wind properly.
It is not a difficult repair by any means but will require a few tools to accomplish this job as well as a little patience. I will try to explain and show you some different possibilities of what the problem could be as well as how the setting system works. Even though the movement I am going to use is an ETA 2824, other watch calibers will have the same type of components that may look a little different but will operate in an analogous way.
Some tools you will need are:
1) Hand levers
2) Hand inserting tools
3) movement holder
4) case cushion
5) tweezers
6) eye loupe
7) 1.2 mm or 120 screwdriver
8) A secondary holding stick of some kind
Also, if this is a movement that is not being fully serviced, finger cots are recommended.
Ok let us get started
As you probably have seen a million times, you cover the watch hands with some sort of thin plastic and use the levers to gently pry up the hands.
Now you must remove the dial. On the other side of the movement are two dial feet clamps. To open them, gently insert your tweezers and slid them out.
Just flip the movement over and the dial should just pop off. Do not forget to push the dial foot clamps back into there normal position so they do not get damaged.
Now we are looking at the dial side of the watch and specifically at the setting train. The area we are going to need to get to is directly in from of the stem. To get to, it we will need to remove the ‘Minute Wheel Train Bridge” as well as the “Date Jumper Maintaining Plate”
Now with the date indicator removed we can remove the rest of the wheels of the setting system. The Hour wheel, the minute wheel, the date corrector, and the setting wheel.
Not the setting wheels teeth are curved on one edge. This faces up.
Now you are looking at the setting parts that work the winding stem as they are properly installed.
Before anything else is taken apart, this is the first thing you want to check. The Setting Lever Jumper has a spring on one end that keeps tension on the yoke. The yoke sits in the slot of the sliding pinion. The sliding pinion moves back and forth on the winding stem. Since the yoke is under tension it allows the sliding pinion to stay tightly meshed with the winding wheel to hand wind your watch. This happens in the first crown position. Compare it to the picture above which shows its correct position on the Yoke.
When the crown is pulled out to the 2nd position, the sliding pinion moves forward and meshes with the setting wheel. The setting wheel interacts with the date corrector and is what changes the date indicator ring to quick date change function.
Then when the crown is pulled out to the 3rd position the yoke advances the sliding pinion, which stays meshed with the setting wheel by the action of the corrector lever and comes in contact with the minute wheel. This allows the wheels of the setting train to advance the hour and minute hand as well as turn the
If this spring is not sitting properly beside the end of the yoke the sliding pinion cannot properly function.
The setting lever jumper has several distinct functions.
The blue arrow shows the jumper. In locks the top pin of the setting lever into three different positions.
The red arrow points to the arms that holds the yoke into the sliding pinion.
The black arrow points to a spring that holds the setting lever flat against the plate. When you press stem release post to release the winding stem, this is what is providing the spring tension allowing it to move back and forth.
The Green arrow points to the spring that keeps the yoke under tension when the sliding pinion is in the winding position.
This is the yoke. The yoke controls the position of the sliding pinion as it slides back and forth on the winding stem. Its position is controlled by both the corrector lever and the setting lever.
On fault that can happen is that the yoke comes out of the groove in the sliding pinion and gets in between the sliding pinion and winding wheel. This can happen due to the screw that holds the setting lever jumper is loose or the yoke itself has become bent.
28 сен 2024
