Watch stops when date change starts

[Adamsky]

Hi. I just stripped and services a nice longines with date change. The watch keeps excellent time but stops ticking just before midnight when the date starts to change.

Before I strip it down I though I would ask where to look.

 

Thanks

 

Adam

[anilv]

The datewheel could be worn... are there any ridges or burrs? Another reason could be a mainspring in poor condition or barrel walls lubricated wrongly resulting in early slipping/poor power.

Also check that the jumper and its spring is correctly fitted.and not binding. Date change wheels are usually shouldered so check that you haven't got the wrong one in.

Also was the date change working before you worked on it?

Anilv

 

[Adamsky]

Thanks for the reply. The watch had been sitting not working before I serviced it. The date does jump when advancing the hands manually. The seconds keep ticking but the hour and minute get stuck when the date starts to change.

 

 

[anilv]

Did you change the mainspring? or at least take it out of the barrel to examine if its still is good?

Apart from mainspring, you need to get the dial off and observe the datechanging parts closely while winding the hands forwards.

What movement is this?  I believe the cal.990 is sensitive to date-wheel condition.

Anilv

[rodabod]

17 hours ago, Adamsky said:

Thanks for the reply. The watch had been sitting not working before I serviced it. The date does jump when advancing the hands manually. The seconds keep ticking but the hour and minute get stuck when the date starts to change.

 

 

If the seconds keep running then it suggests that the watch amplitude is sufficient, ie. the watch movement isn’t actually stopping. 

Does the date changeover feel smooth when you manually advance it? Check for wear and correct lubrication. 

Also, does the canon pinion feel tight enough when you go to adjust the time? It’s hard to describe the right amount of resistance, but it should be noticeable. 

Edited December 21, 2017 by rodabod