Landeron 47 (48) stops after a minute

[Khan]

Hi

When the centre seconds wheel reaches around 57 seconds and its teeth beneath touches the "Intermediate" wheel next to the minute wheel, the watch stops. When I turn on those two wheels manually when they are free, it feels sticky - is it just a cleaning or an adjustment/repair? 

And if someone knows the history of the cal. 47, kindly let me know. Like how many were made and for what purpose etc. 

Edited November 1, 2024 by Khan

[caseback]

Did it run ok before or did you get it like this? When was it last serviced? 

[rjenkinsgb]

Is that intermediate wheel adjustable for depth of engagement with the centre seconds wheel?

It looks to me like the the tooth engagement is too shallow and they may be contacting near end-on and blocking rather on the sides of the teeth, where the load should be transferred??

Some of the intermediate wheel teeth look mis-shapen, with a step at the present engagement depth - as they mesh like that, they can wedge together.

[Khan]

7 hours ago, caseback said:

Did it run ok before or did you get it like this? When was it last serviced? 

I got it like this, dont know the service history unfortunately. 

6 hours ago, rjenkinsgb said:

Is that intermediate wheel adjustable for depth of engagement with the centre seconds wheel?

It looks to me like the the tooth engagement is too shallow and they may be contacting near end-on and blocking rather on the sides of the teeth, where the load should be transferred??

Some of the intermediate wheel teeth look mis-shapen, with a step at the present engagement depth - as they mesh like that, they can wedge together.

At the Green Arrow, thats the adjustment screw. I tried to get the Intermediate wheel teeth closer to the centre Chrono wheel but it still stops, also at other teeth of Intermediate wheel. 

[praezis]

This happens if the pivots of sliding gear wheel and min. recording runner are blocked by dirt and old oil (both shall not get oil).

Disassemble and clean them.

Frank

[nevenbekriev]

Read all this

 

[Khan]

I figured out that the dial hole at the minute counter isnt centered. How to fix that? Is the dial foot Bent? And the hour, minute and seconds hands seems to sit stuck and dry. How to take them off without bending the dial? 

On 11/1/2024 at 2:30 PM, praezis said:

This happens if the pivots of sliding gear wheel and min. recording runner are blocked by dirt and old oil (both shall not get oil).

Disassemble and clean them.

Frank

The reason was that the dial hole for the minute counter isnt centered. When I take off the minute counter hand, the chronograph functions perfectly. 

[caseback]

The watch has most likely been dropped or bumped. And, as the service history of it is unknown as well, I suggest you take it apart completely and do a full service. Could it be that you are trying to avoid doing that? During disassembly and inspection, this cause of the chronograph stopping after a minute would have already been found. The same thing with your question on the dial feet: disassemble and find out. The a dial foot might be bent or broken. I'm afraid none of us can see that looking at the photo you provided.

Edited November 5, 2024 by caseback
Rephrase

[Khan]

2 hours ago, caseback said:

The watch has most likely been dropped or bumped. And, as the service history of it is unknown as well, I suggest you take it apart completely and do a full service. Could it be that you are trying to avoid doing that? During disassembly and inspection, this cause of the chronograph stopping after a minute would have already been found. The same thing with your question on the dial feet: disassemble and find out. The a dial foot might be bent or broken. I'm afraid none of us can see that looking at the photo you provided.

You are right, I was hoping to not do a full service to avoid the risk of unnecessary wear during (dis)assembly but since Id love to wear it regularly and dont like the thought of a super dry mainspring and barrel, it needs to get a full service so will start doing that. By the way, the pivot in the dial hole at 3 o clock is located south of the hole. But the other dial hole at 9 o clock is perfectly centered. 

Edited November 5, 2024 by Khan

[Khan]

I have now diassembled the watch and see Bent dial feet, why it was struggling to come off the movement. How to the straighten them? 

And should I order a new spring? The very old one looks tired. It was running fine though but didnt check the amplitude. 

[caseback]

3 hours ago, Khan said:

I have now diassembled the watch and see Bent dial feet, why it was struggling to come off the movement. How to the straighten them? 

And should I order a new spring? The very old one looks tired. It was running fine though but didnt check the amplitude. 

- with care and small steps with a small pair of pliers. Look at where the dialfeet are and where the dial needs to go, then you know which way to bend it.

- Yes, that is the sensible thing to do imo.