The What Was The Problem Thread.

[jdm]

This can be funny and challenging. Present a problem without immediate evident cause, of which the cause has been found and fixed, give some elements, and let other guess. The cause must be a very definite fact please, not just "it was dirty inside" :)

I'll begin with what happened to me today. Seiko movement is disassembled for servicing. It is put back together the bare minimum to have it run, at first it runs but because of poor amplitude and large positional variance the balance cock is removed to examine and manipulate the hairsping, this two or three times but all of a sudden it starts making snow on timegrapher which doesn't reveal amplitude (sorry no pic). Removing the balance again doesn't reveal anything visually.

Anybody?

Edited January 29, 2016 by jdm

[Marc]

Hair spring coils fouling the under side of the balance cock?

[jdm]

Hair spring coils fouling the under side of the balance cock?

Nope the hs looked horizontal and clear of other objects.

[Geo]

Did you inadvertently magnetise the hairspring?

[jdm]

Did you inadvertently magnetise the hairspring?

No sir.

[Geo]

Was the end of the hairspring slack in the stud or collar?

[jdm]

Was the end of the hairspring slack in the stud or collar?

 

You got it right! I had an hint when, in despair I poked the stud arm a little and it started behaving, just to go crazy again after few moments. I was puzzled. Then with the balance removed again I found the hairspring was moving freely in the end stud. Pressed it and it's good so far.

Edited January 29, 2016 by jdm

[StuartBaker104]

Im so glad we know now. Was worrying about this as I went to sleep last night! I was going for stud screw loose as I saw something similar recently

[joelcarvajal]

This is a very interesting thread! So much to learn from.

[joelcarvajal]

I'll give it a shot.  But since I am such an amateur watch repair hobbyist, this case might be a no-brainer for many of you who are already experts.

 

Early last year, I received a non-working 1969 Omega Constellation featuring the venerable Omega 751 movement.

 

After replacing many parts, I was able to restore the watch.  

 

The problem was, the watch will run for several hours and keep good time but once it stops, with the second hand between the 35 to 40 second mark, it will stop intermittently after that.  The second hand will stop at the same spot everytime - around the 35 to 40 second mark.  

 

Shaking the watch, moving the stem, adjusting the time will restart the watch.  

 

There was no problem with the way the hands were installed.

 

At first, i thought it was due to a fiber (we have a yorkie running freely inside the house) on the escape wheel, but, even after striping and cleaning the movement, the watch will still stop the same way].  

 

When it runs, the second hand moves smoothly.  When the second hand stops, everything in the watch stops.

 

Here's a picture of the movement *before* I found out (or rather, I fixed by trial-and-error) the problem.  Note that the auto-wind mechanism was removed in this picture.

 

[JimInOz]

Hard to say without a decent pic, but............broken tooth on the third wheel?

 

That friction spring looks a bit dodgy too.

[Geo]

My first thought was the centre second friction spring, it's well distorted and looks like it is resting on the pinion and not the end of the pivot.

[oldhippy]

That friction spring isn't even on the center of the pivot it looks as if its more to the side and well out of shape.  

[joelcarvajal]

I knew it was too easy for you guys.   :bow:

 

In my case, I first suspected the slightly bent sweep second hand pinion.  But I figured it could not have caused it to stop at the same spot.

 

I also suspected a tooth of one of the gears in the train was damaged but after inspection, everything was in order.

 

I ignored the friction spring thinking that as long as it presses on the second hand pinion, it won't matter that it was not centered.  As it turned out, its edge/corner blocked a particular pinion leaf from turning.

 

Adjustment of the friction spring to proper shape solved the problem - and my hair pulling.   :thumbsu:

[JimInOz]

So I have a little AS1686. The previous owner mentioned that he had trouble winding and setting the time.

 

All of the parts are shown below.

 

What is your diagnosis?

 

[Marc]

Looks like the détente has broken off the set bridge/cover plate for the keyless works.

[JimInOz]

Looks like the détente has broken off the set bridge/cover plate for the keyless works.

 

 

Wow, didn't take long at all, I'll have to find a harder one next time ;-)

 

Part on order, just have to wait for it to travel from the other side of the planet.

[Geo]

Damn, I was going to say "'cause it's in bits" :D

[oldhippy]

Looks like the détente has broken off the set bridge/cover plate for the keyless works.

Agree. It should have a little arm that has broken off. In some movements with this fault when you go to wind it changes into setting the hands because the piece that prevents this happening has broken it can also jam the winding and won't wind.

[mwilkes]

Here's one that got me: The watch only ran when the cannon pinion was removed.... Guess what the problem was.

[matabog]

If the keyless-works were in place, they might have been dirty. Or the intermediate minute wheel had a problem.

 

Maybe dirt or other things might have got in between it and the mainplate. Or maybe it was bent and touching the mainplate creating excessive friction.

Edited February 2, 2016 by matabog

[mwilkes]

Close, but not quite! The keyless works were in perfect condition, but the cover-plate was VERY slightly bent - just enough to snag a tooth of an intermediate wheel.