Landeron 148 chronograph feature only starting and resetting, no pausing

[Max50916]

Beginner horologist here. I attempted to overhaul my first chronograph. I followed the manual from cousins to the tee from what I can tell, and everything is working great EXCEPT the chronograph will only start, and when I hit the bottom button to pause, it automatically resets to zero instead of pausing before a second click to reset. What would cause this? I've been scratching my head since it essentially works perfectly otherwise. Any help would be great appreciated!

[JohnR725]

It might be nice if you gave us a picture looking straight down at the chronograph with as much detail as you can.

One of the minor problems with the chronographs are and it's mentioned in the manual not all screws are screws. Some of the screws are for adjusting things and if you rotate them without knowing what you're doing that would be bad.

[nickelsilver]

Yes, a pic would help. The flyback lever can need some adjusting on these, they are usually filed a bit. But even if it needs filing it wouldn't cause this problem- it usually means it "blocks" when trying to stop the chrono.

 

What can happen that would cause your issue is the cam (called mounted hammer in the tech sheet) doesn't advance fully when the chrono is started. In this case the flyback lever will interact with it as though it's in stop position- but the cam has advanced just enough to engage the coupling clutch and lift the brake*.

 

A photo in the run position would help see this. Also, if you are accustomed to other (most) chronographs these work differently, usually the button at 2 o'clock  start/stop, at 4 o'clock zeros. On this one the 2 o'clock starts, 4 stops, 2 starts again if wanted, or hit 4 two times to stop then zero.

 

Here's a link to Cousins tech manuals on the Landeron chronos, which will help with nomenclature and servicing.

https://www.cousinsuk.com/document/category/landeron-movement-parts

 

*on edit- forgot these don't have a brake.

Edited January 20, 2021 by nickelsilver

[canthus]

Just a thought, do you not press the top pusher to start, pause, and restart and the bottom button to just reset to zero. I may be wrong,

[Max50916]

5 hours ago, nickelsilver said:

Yes, a pic would help. The flyback lever can need some adjusting on these, they are usually filed a bit. But even if it needs filing it wouldn't cause this problem- it usually means it "blocks" when trying to stop the chrono.

 

What can happen that would cause your issue is the cam (called mounted hammer in the tech sheet) doesn't advance fully when the chrono is started. In this case the flyback lever will interact with it as though it's in stop position- but the cam has advance just enough to engage the coupling clutch and lift the brake.

 

A photo in the run position would help see this. Also, if you are accustomed to other (most) chronographs these work differently, usually the button at 2 o'clock  start/stop, at 4 o'clock zeros. On this one the 2 o'clock starts, 4 stops, 2 starts, again if wanted, or hit 4 to times to stop then zero.

 

Here's a link to Cousins tech manuals on the Landeron chronos, which will help with nomenclature and servicing.

https://www.cousinsuk.com/document/category/landeron-movement-parts

 

7 hours ago, JohnR725 said:

It might be nice if you gave us a picture looking straight down at the chronograph with as much detail as you can.

One of the minor problems with the chronographs are and it's mentioned in the manual not all screws are screws. Some of the screws are for adjusting things and if you rotate them without knowing what you're doing that would be bad.

Sure thing, here's a photo of the chrono running and stopped. I've put in a video too showing the start/reset

[nickelsilver]

Ok, it's not going all the way to the run position. The mounted hammer (cam) should be lifting one step higher. That is the stop position, so the eccentrics have been played with in the past. In the pic eccentric 1 adjusts how deep the coupling clutch engages with the chronograph runner. This is out of play in the stop position. Eccentric 2 adjusts how far the mounted hammer lifts the coupling clutch when it stops the chrono. This will definitely need adjustment. 3 adjusts the lifting of the sliding gear when it is zeroed, and 4 adjusts the depth of the sliding gear when the chrono is running.

 

What you need to figure out first of all is why it isn't going all the way to the run position. These aren't the best chronos (but they're good)- they count on a button push to start to be forceful enough to jump the mounted hammer to run position; either something is blocking the pusher, or the operating lever, or less likely the mounted hammer itself.

 

 

[Max50916]

8 hours ago, nickelsilver said:

Ok, it's not going all the way to the run position. The mounted hammer (cam) should be lifting one step higher. That is the stop position, so the eccentrics have been played with in the past. In the pic eccentric 1 adjusts how deep the coupling clutch engages with the chronograph runner. This is out of play in the stop position. Eccentric 2 adjusts how far the mounted hammer lifts the coupling clutch when it stops the chrono. This will definitely need adjustment. 3 adjusts the lifting of the sliding gear when it is zeroed, and 4 adjusts the depth of the sliding gear when the chrono is running.

 

What you need to figure out first of all is why it isn't going all the way to the run position. These aren't the best chronos (but they're good)- they count on a button push to start to be forceful enough to jump the mounted hammer to run position; either something is blocking the pusher, or the operating lever, or less likely the mounted hammer itself.

 

 

This is incredibly helpful thank you so much! Will mess around with it and see what I can do!

[Max50916]

On 1/20/2021 at 9:48 AM, nickelsilver said:

Ok, it's not going all the way to the run position. The mounted hammer (cam) should be lifting one step higher. That is the stop position, so the eccentrics have been played with in the past. In the pic eccentric 1 adjusts how deep the coupling clutch engages with the chronograph runner. This is out of play in the stop position. Eccentric 2 adjusts how far the mounted hammer lifts the coupling clutch when it stops the chrono. This will definitely need adjustment. 3 adjusts the lifting of the sliding gear when it is zeroed, and 4 adjusts the depth of the sliding gear when the chrono is running.

 

What you need to figure out first of all is why it isn't going all the way to the run position. These aren't the best chronos (but they're good)- they count on a button push to start to be forceful enough to jump the mounted hammer to run position; either something is blocking the pusher, or the operating lever, or less likely the mounted hammer itself.

 

 

 

On 1/20/2021 at 1:31 AM, JohnR725 said:

It might be nice if you gave us a picture looking straight down at the chronograph with as much detail as you can.

One of the minor problems with the chronographs are and it's mentioned in the manual not all screws are screws. Some of the screws are for adjusting things and if you rotate them without knowing what you're doing that would be bad.

Here's an update! After many hours of fiddling and frustration I discovered that the reverser spring was slightly warped, this was preventing the hammer from functioning properly. I replaced the part and now it's running!