Landeron 248 Main Seconds Hand Stuck

[AndreiMartin]

Hello all,

I'm looking for an advice on what could the issue be on my Landeron 248 movement. When I start the Chronograph, the main seconds hand runs until the 56-57 seconds mark and then it suddenly stops but if I reset the Chronograph function, the watch starts running again.

When not using the Chrono, the watch runs fine.

Since I had it, the watch hasn't been serviced at all and I only wore it maybe 3-4 times in 3 years.

If you're kind, please advise if this could be something serious or just maybe cleaning related.

Thank you all,

A.M.

 

[nickelsilver]

There's an issue with the minute counter. Could be the jumper spring is adjusted too strong, or the depthing with the chrono runner finger not correct, could even be the minute counter hand touching the dial.

[AndreiMartin]

22 minutes ago, nickelsilver said:

There's an issue with the minute counter. Could be the jumper spring is adjusted too strong, or the depthing with the chrono runner finger not correct, could even be the minute counter hand touching the dial.

Hello and thank you for the reply!

I checked if the minute hand is touching the dial and it looks fine. The Chrono worked up until today so I guess could be one of the two issues you mentioned.

What do you mean by "the depthing with the chrono runner finger not correct"? Are they the two cams that are on the seconds and minute wheel or something else?

 

A.M.

43 minutes ago, nickelsilver said:

There's an issue with the minute counter. Could be the jumper spring is adjusted too strong, or the depthing with the chrono runner finger not correct, could even be the minute counter hand touching the dial.

Checked another post where you've given some advice to someone else regarding a Landeron 248 issue. The minute wheel spring seems fine and not to much tension on it. I actually tried to disengage the spring when the center seconds hand is reaching the 56 seconds mark and the watch still stops. So it might be depthing like you said or other issue.

 

55 minutes ago, nickelsilver said:

There's an issue with the minute counter. Could be the jumper spring is adjusted too strong, or the depthing with the chrono runner finger not correct, could even be the minute counter hand touching the dial.

added two photos if that helps

[nickelsilver]

In the "run" position, the intermediate minute counter wheel drops down toward the chronograph runner. When down, a tooth should be pointing directly at the center of the chrono runner. When the finger on the chrono runner comes around to advance the minute counter, it should cleanly contact this tooth on its ogive, advance it, the jumper takes over and continues the advance, and the finger should brush by the tooth as it continues. It can touch the tooth, but shouldn't cause the minute counter to advance at all.

 

If the depthing is too deep, the finger can contact a tooth in advance, possibly arc-bout , or tip-to-tip, causing it to block. If it is too light, but the position of the intermediate wheel isn't such that a tooth is pointing at the chrono runner center, the same issue can arise.

 

To center the intermediate wheel, you reposition the minute jumper. If you find you have to change the depthing, this will affect the centering as well- perhaps not enough to matter, but it may be. This is because as the intermediate wheel comes toward the chrono runner, it rotates around the minute counter wheel. So it can be a bit of a back and forth.

 

The eccentric for the depthing of the sliding gear (the part on which the intermediate minute counter wheel is fixed) is at the red arrow in the pic. Something to check as well, is the freedom of the sliding gear. It is acted on by a wire spring, and it should be very free. It's held in place by a shoulder screw (or two, can't remember), if it isn't free, and everything is clean, it might need to have the underside of one/both of these screw heads retouched. You can test by simply loosening the screw a fraction of a turn.

 

If you reposition the minute counter wheel to correct the intermediate wheel's position, you may have to adjust the hammer. When in zero position, the hammer for the chrono runner should be in full contact with its heart cam, and the hammer for the minute counter should allow a slight freedom of the cam. You should be able to push the minute counter wheel in both directions, with the cam coming into contact with the hammer before the jumper tip goes over a tooth. The big screw on the hammer alters the spacing; but you may find that with everything positioned well, and good contact with the chrono runner, you have too much freedom in one direction and none in the other. In this case you must file the face of the hammer slightly to favor freedom in the correct sense. The face must be repolished too. I have done this many times, but don't recall having to do it on a Landeron x48 family.

 

 

Edited September 9, 2024 by nickelsilver