Omega cal 354. Can poorly fitted stem cause movement to stop?

[chriz74]

Some days ago I got my Constellation back from sweep seconds hand repair. The watch was stopping randomly once every few hours. Two days ago it was not moving so I pulled the crown and it came out with all the stem. After pushing it back (and later opening the case to tighten the screw) it started working normally without stopping. This is no hacking movement , how could that lose screw cause stopping?

[watchweasol]

The first thing to check is the clearance of the sweep seconds, It may have been catching the batons (hour markers) or the other hands. If the stem wasn't secure the movement may have moved slightly, did you check that the movement was secured with its clamps/screws  as  if the stem screw was loose ther may be a loose screw or other debris in the movement.  Was the second hand only attended to or was it cleaned etc.

attaches is the tec/parts sheet

1367_Omega 354 (2).pdf

[chriz74]

No catching no. The seconds hand didn’t stay in place so he managed to tighten the hole I guess. Didn’t check the clamp I will open it again later.

[watchweasol]

Great, best to check the obvious thins first.  Is it running ok now.

[chriz74]

Hmm no. It stopped again albeit having run for several hours. It stops more or less always in the same position 

[watchweasol]

When you restart it do you give it a shake and does it then run again ok and stops always in the same spot,  It still might be some debris in the movement or has been found before a bit of the bumper spring broken off and wandering about the movement . I think the best thing to do if you are confident enough is to get it de cased and run it under a cover (wine glass) and when it stops again have a look round for debris, bent or broken tooth on the train wheels.  If it hasn't been serviced at all its best to do that as well, as it may have a broken mainspring also.

[Nucejoe]

 When you pull the stem out, some  part of the keyless are free to jump out of position, you will then have a mess that can easily engage the minute train or date change mech or helplessly stuck somewhere, in which case, you have no choice but to get to the keyless and set every part right. 

Weasol is trying and hoping for the best senario, he needs more data.

Regs

 

[chriz74]

So I tried to wound it like 60 times and put it on a shelf for 3 times . The watch keeps running on average for 27 hours then stops. Strange as reserve should be 42 hours and the spring was changed in the last servicing (some years ago). Watch seldom used, it was on a winder for like 2 years straight though then I removed and never used it for 3 years more or less

[jdm]

37 minutes ago, chriz74 said:

Strange as reserve should be 42 hours and the spring was changed in the last servicing (some years ago).

Had you checked the power reserve at that time?

37 minutes ago, chriz74 said:

 it was on a winder for like 2 years straight though then I removed and never used it for 3 years more or less

2 years on a winder seems an excellent way to unncessarily wear out an automatic watch in all its parts. Good at least that it was then given a break.

Anyway, since the watch has been just returned from repair, your first action should be to return to it. It is fair to give them a chance to set things right.

[watchweasol]

Hi  I would certainly agree with jdm's sentiments,  Regarding the repair return it and explain the problem and as jdm said

1 hour ago, jdm said:

It is fair to give them a chance to set things right.

 

[anilv]

Hi Chriz

If it always stops in one position you may have a power transmission problem.

1. Remove balance and pallet fork.

2. Put half a turn on the barrel and let it stop.

3. Use a fine marker (0.5mm) and mark the edges of the wheel and barrel at the same poin.. eg pointing away from you. The actual position may be dictated by wheel overlap etc.

4. Put another half wind and see if any of wheels/barrel end up in the same position. 

My guess is one of the barrel teeth may be damaged but it could also be some dirt (or damage) in the pinions. As the power in the barrel progressively decreases it will reach a point where it is no longer sufficient to overcome the dirt/damage and it stops.

It could also be bad pivot jewels/holes which wont show up in the above check.

Anilv