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Posted

Hello everyone,

The pride of my watch collection, a JLC Master Geographic (cal 929/3, which is based on the 889), is giving me some worries. I've noticed for a long time that it doesn't wind very efficiently -- on a regular office day it'll just keep it's level of charge. Thus, if I wear it during the day and put it down during the night, it'll be dead after a couple of days. It has a power reserve indicator, so it's easy to see.

1-2 years ago, I had been to the JLC boutique in Geneve and to a reputable watchmaker in town and both told me not to worry and to just wind it manually sometimes.... otherwise it runs very well. Amplitude close to 300°, perfect lines, very high accuracy. 

Just recently, though, it noticed a bit of a rattle when gently shaking the watch next to my ear. 

Now I opened it and noticed quite a bit of play in the rotor. It doesn't touch the movement, though. Here are some GIF videos and a picture.

Does anyone have experience on the acceptable/desirable amount of play in the rotor? Is this ok or does it need to be replaced? I don't have any experience with ball bearings, so don't know what's normal. On an axle/bushing type rotor I'd consider this too much. 

20240109_095333_1.gif.061b3e63f1d0c469c983eb0104b92a41.gif20240109_095333_2.gif.df4f97d6967482672074612c2a4c3354.gif20180705_105129-Copy.thumb.jpg.4a2236820f0da26abdfe1dc9cb10cd2c.jpg

Apart from counting on everyone, I'm particularly looking at @Kalanag, @ahabec who have posted about this calibre on this forum.

Posted (edited)

The play looks acceptable to me.

A design fault of this movement seems to be the rocker mechanism of the automatic works. The wheels are both riveted to the rocker plate, so the pivots can not be cleaned and lubed properly. Furthermore the teeth of the wheels are prone to wear. That’s most likely the reason why JLC changed the design of this movement from bidirectional to unidirectional winding.

IMG_5463.jpeg.3b476879a25bd77da579210bcee309a3.jpeg

IMG_8628.jpeg.dae1c66b59aa88fa347e22346ff8e19c.jpeg

Here is the unidirectional redesign:

IMG_5464.jpeg.d992175f963dc8f684ed535111c9589e.jpeg

Edited by Kalanag
  • Like 1
Posted
On 1/11/2024 at 8:33 AM, Kalanag said:

The play looks acceptable to me.

A design fault of this movement seems to be the rocker mechanism of the automatic works. The wheels are both riveted to the rocker plate, so the pivots can not be cleaned and lubed properly. Furthermore the teeth of the wheels are prone to wear. That’s most likely the reason why JLC changed the design of this movement from bidirectional to unidirectional winding.

IMG_5463.jpeg.3b476879a25bd77da579210bcee309a3.jpeg

IMG_8628.jpeg.dae1c66b59aa88fa347e22346ff8e19c.jpeg

Here is the unidirectional redesign:

IMG_5464.jpeg.d992175f963dc8f684ed535111c9589e.jpeg

Oh really? I'm surprised. It doesn't "feel" right to me. But I hope you are right! The replacement pieces are very expensive. 

Thanks for the info on the rocker mechanism! Maybe that's the source of the inefficient winding. I'll inspect. 

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