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panchoskywalker

eta 2784 question

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This was an interesting question, I'll take a first shot!
Sounds like a mainspring unwinding in the barrel.
It might be the little indentation on the side of the barrel that become a bit round, it can retain a little bit of tension but finally slips.

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5 minutes ago, HSL said:

This was an interesting question, I'll take a first shot!
Sounds like a mainspring unwinding in the barrel.
It might be the little indentation on the side of the barrel that become a bit round, it can retain a little bit of tension but finally slips.

That's what I was thinking...not with those professional words.

That isn't normal is it?

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You have to take the movement apart, just by sound one  can identify the area that might be subject to repair.
After a closer inspection one can say exact whats erratic or needs to be repaired. 

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The most likely parts are the barrel, the barrel arbor and/or the mainspring, but you wont know which until you inspect them closely.
It could also be that there is play in the barrel bearings or movement in the plate(s) holding the barrel in place (a broken screw perhaps), allowing the barrel  to rock or slip when there is sufficient tension in the spring.

My money is on the mainspring, but I'm usually wrong.
 

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11 minutes ago, AndyHull said:

The most likely parts are the barrel, the barrel arbor and/or the mainspring, but you wont know which until you inspect them closely.
It could also be that there is play in the barrel bearings or movement in the plate(s) holding the barrel in place (a broken screw perhaps), allowing the barrel  to rock or slip when there is sufficient tension in the spring.

My money is on the mainspring, but I'm usually wrong.
 

Thanks! That should be fun. :-I

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If the whole barrel is slipping, you can possibly spot that without stripping the thing down. I have an old EB8800 that makes similar noises, in my parts pile, and I know why it misbehaves, because I can see the barrel spinning rapidly when I wind it more than a few turns, because the whole barrel lifts up at one side as it is wound.

The cause is a broken hold down screw on the rather flimsy barrel bridge. The screw head is missing in that mech, and the shaft of the screw is still in the base plate, which is why I haven't bothered fixing it yet, as I haven't had the time or inclination to try to extract it yet.

RIMG0392.thumb.JPG.e0390206a318a4c69f5584f0b636ef92.JPG

The EB880 is a pretty basic mechanism, as you can see, and this seems to be a known weakness in that particular setup. It is also much easier to see the barrel in that case, because it is staring you in the face.

The picture above is of a similar (pin lever, rather than jeweled, but working) EB8800 with two unbroken screws, so you can understand what I am talking about. 

Watching the barrel on your watch might be a little more tricky. Having said all that, even if you do spot the barrel slipping, you will still need to strip things down to figure out why. 

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1 hour ago, Nucejoe said:

Judging by the number of turns before release, mainspring dislodges from thr barrel.

 

 

When I wear it I don't have any problem, it never stops, but that sound when I handwind it got my attention.

What makes you think it's the mainspring? When that sound comes the barrel does not move...so the sound got to come from inside the barrel, is that the logic?

 

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There aren't that many parts to choose from, barrel, mainspring and the arbor.
Watching the video one can see you wind and the balance oscillate, it means you got power through the drive train.

If the mainspring would be bad by the arbor then you wouldn't have any power since it would  not wind the mainspring at all, now it does and by that tighten itself around the arbor notch. 
On the inside of the barrel you have the small indentation I earlier spoke about, the mainspring has a formation which grabbs onto this notch and makes it possible to wind without the spring slipping.
On your watch the spring grips onto this notch until the tension in the spring makes it to slip. As it  unwinds it grows in area and once again grabs onto the notch making your watch run.
So the watch will still run but not as long as it should in a static position. 
It is an easy fix but you have to open the barrel to see if it is the end of the spring that is bad or the notch in the barrel.

Forgot to say, when you wear it the auto winder probably nerver winds it enough to release the spring  or you just do't notice it,

Edited by HSL

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1 hour ago, panchoskywalker said:

ok, I think I understand now. Thanks for the explanation.

Sometimes pictures are better than words so here is a PDF with some pictures of the components we been trying to describe.
 

Barrel Complete.pdf

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2 hours ago, panchoskywalker said:

When I wear it I don't have any problem, it never stops, but that sound when I handwind it got my attention.

What makes you think it's the mainspring? When that sound comes the barrel does not move...so the sound got to come from inside the barrel, is that the logic

 Mainspring dislodges from the notch inside the barrel, it's coil turns to unwind to release the power. 

 

2 hours ago, panchoskywalker said:

When I wear it I don't have any problem, it never stops, but that sound when I handwind it got my attention.

What makes you think it's the mainspring? When that sound comes the barrel does not move...so the sound got to come from inside the barrel, is that the logic?

 

The question was, what dose that sound mean? It means the mainspring dislodges from the notch inside the barrel therefore unwinds to release some or all of its power reserve. No telling if the barrel is reuseable or should be replaced before you crack it open.. Should you need any help I get my tools :judge: and stay with you step by setp if neccessary  til fixed.:lol:

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Yes that is one good reason/ logic, if you can tell where a sound is generated.

In this case, however,  familiarity with the sound and commonality of the culprit helps a lot.

Manufacturers recommend MS removal routinely at periodic cleaning/services, MS springness weakens by use. Use of right grease and oiling the arbor is a must. Some barrels says do not open.

As OH puts it, you don,t know what is happen inside unless you open the barrel.

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1 hour ago, panchoskywalker said:

I was more thinking about looking for a complete barrel to just replace it, not sure if I have the guts to open the barrel, would probably find the way to stick that spring into my eye.

That is certainly an option. They should be available, and hopefully not eye wateringly expensive either, however it may be possible to fix the one you have. Just put on your safety specs and crack it open.

I think a 2770 series barrel and mainspring would be correct, but check before you purchase.

Something like this perhaps - https://www.ebay.co.uk/itm/ETA-Calibre-2770-Part-182-Complete-Barrel/222524899179?hash=item33cf847f6b:g:NLkAAOSw4CFYwvVt

Also confirm with the supplier that it includes the spring.

Edited by AndyHull

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4 hours ago, AndyHull said:

Also confirm with the supplier that it includes the spring

As the price indicates these usually comes with just the barrel drum and cover.
The problem with buying complete parts to old movements is that you don't know when it was fabricated. Old non synthetic oils gets bad with time and it ends up you have to pop the cover sooner or later anyway.
 

Edited by HSL

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43 minutes ago, HSL said:

As the price indicates these usually comes with just the barrel drum and cover.
The problem with buying complete parts to old movements is that you don't know when it was fabricated. Old non synthetic oils gets bad with time and it ends up you have to pop the cover sooner or later anyway.
 

Agreed. At some stage, you are going to have to bite the bullet and take a look at the spring, whether it is the old one, or the replacement.
Besides it may be a simple fix, so you might not need to stump up for one or other or both of the  barrel and/or the spring.
I guess it could be simply that everything is so gummed up with old oil and dirt, that the spring simply isn't catching on the barrel. Alternatively, it might only take two minutes with a sharp file to fix the issue.
Furthermore, in the extremely unlikely event that you do take an eye out with the spring, whats the problem? You can still see to type "I told you so" with the one remaining good one. :devil:

 

Edited by AndyHull

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Guess I'm a little bit zealous sometimes, but found  out the hard way it is just easier to bite the bullet and take the loooooong way and make it correct from the beginning.

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26 minutes ago, HSL said:

Guess I'm a little bit zealous sometimes, but found  out the hard way it is just easier to bite the bullet and take the loooooong way and make it correct from the beginning.

I agree, shortcuts often turn out to be the long way of doing things. As the old adage goes, check it twice, fix it once, or to put it another way, you need to fully understand a problem before you can resolve it.

Edited by AndyHull

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Ultimatety no exception to the cat , box and cyanide in quantum mechanics, OH and niel bohr are saying the same thing. 

All indications are MS dislodges from the barrel notch, however, if this presumption  turned out wrong, you will be the proud owner of a pair good of  barrel drums. the chance you don,t have ţo take.

There are approaches to safe removal of MS. 

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