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Landeron 248 disassembly videos


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Since I was working on the Landeron 48 with wrong dial, from which I used the case and a Landeron 151 and correct dial to make a new watch, I saw this Landeron 248 sitting in the drawer at my desk and devided to finally tackle the issue it had: a slipping mainspring.

I documented the disassembly of the movement vith 3 videos, the first of which is here below:

Hope you enjoy

 

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On 3.4.2017 at 8:14 AM, matabog said:

MS slipping - was the problem the end piece of the MS? The one that catches the groove in the MS barrel?

Actually no,the issue is that the mainspring slips on the arbor, so i am not so sure the new mainspring will suffice, probably will need to replace the entire barrel assembly including the mainspring... At the moment I do not have time to work on this movement unfortunately, so it will have to wait.

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It might not be a barrel arbor/MS problem. 

Another scenario could happen: it is very hard to see because the crown wheel is beneath the wheel train bridge. 

Normally, when you turn the crown, you actually turn the sliding pinion (clutch wheel) which turns the winding pinion (under the force of the yoke and yoke spring); then the winding pinion turns the crown wheel, which turns the ratchet wheel, which finally turns the barrel arbor 
Because of poor oiling or wear, two things might go wrong: the sliding pinion might disengage the winding pinion (wear on the Breguet teeth), or the winding pinion might disengage the crown wheel (the winding stem might have some wear on it and the winding pinion might be allowed to seat at an angle lower then 90 degrees). There would be a sudden MS discharge that you would see on the crown wheel (aprox 30 degrees in the opposite direction if you drew a dot on it, for example).

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