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ETA2824-2 Balance issue


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Hi all,

One of the reasons I decided to learn watch repair was to be able to maintain my own watch that has an ETA 2824-2 skeleton movement in it. As it happens I also managed to give the watch a bit of a shock - my own stupid fault - and since then it's been running oddly. I first noticed it wasn't keeping time, then with a bit of investigation I found that it ran ok when face up, but came close to stopping face down. I've now taken the movement out, I took the balance out and had a look, it seems ok but i'm new to this!

Now that it's out, the most up-to-date version of the issue is that when either of the shock springs is released the watch goes. As soon as both shock springs are secured the watch stops - like they're too tight or something? I'm happy to provide pictures if that'd help. My usb microscope isn't great, but the end stones look ok to me. The pivot on the lower side of the balance staff looks good. I can't see the other one as the hair spring is in the way, I can remove it to look but this is new territory for me so wanted to ask first! Any advice would be much appreciated.

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 If you removed both end stones , then you should  see the pivot on the dial side too.

 A broken or bent pivot is the most likely senario which usually is visible under high magnification and  rarely loss of end shake due to the shock, hairspring coil rubbing might also cause this.

Does it run strong in all positions when you loosen the cock screw or remove the end stones?  or does it loose  amplitude faced down ?

I don't suppose you yet have a timegrapher to give us some amplitudes, you might instead ink mark a dot on balance wheel and try slo- mo to get an idea of amplitudes. 

Its an etachron so I wouldn't recommend pulling the balance complete for closer inspection, but you can inspect/show a close up of the pivot without detaching cock-balance complete. 

A close up side view vid of the oscilator running be nice to have.

Good luck pal.

 

 

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It's rare for a pivot to get damaged with shock protected jewels (though it does happen). More likely on this caliber is the hairspring got shifted and/or possibly bent; it can happen in a way that would give your symptoms, and seem to be relieved with the added balance freedom of loosening the jewel spring. Some pics would help. If you have a phone made in the last 5 years it will probably suffice for this, no need for ultra close-ups at this point.

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Thanks very much both for the advice so far. The good news is I'm in no rush - haven't been wearing this watch as it doesn't keep time, so keen to take my time and not make it worse.

I attempted to take some pictures this morning, not the best but maybe it's start. The side on of the watch while running (shock spring released) didn't come out great. Nucejoe I don't have a timegrapher yet, but am considering getting one as I do think it'd make things clearer. I tried to video and work out the amplitude but I need to revisit this, the video wasn't very clear. This said, if I correctly interpret amplitude as the angle a single point goes from left to right I'm not convinced it's very good.

The hairspring looks a bit peculiar on the right hand side, but could be reflection off the bridge? 

I really appreciate the help! Regardless of the issues it's been really rewarding so far to take this watch apart. It was not super expensive, but I'm quite attached to it.DSC04707.thumb.JPG.c9fc3bd232694ad290dc2e3120adf62a.JPG

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Terminal curve is,   Ok.

Coil  is concentric,   OK           and seems flat,  Ok. 

The coil should be level  ( ie: not slanted when installed on mainplate)  so not to rub on balance spokes or the cock. Hairspring rubbing increasingly appears to be the problem as Nickelsilver first said, I would hold the movement up close to your eyes to see if it the H/S rubs as the balance oscilates. 

What amplitude would say you have in terms of degrees in face down position? 

Regds

 

 

 

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I had a very close look, I can't see obvious contact between the hairspring and the balance or cock but it's very small! I can't rule it out.

I did manage to get a photo of the other pivot though, and it seems to be there and not obviously bent. I also took some slow mo shots with my phone camera to try and guage amplitude. I believe the idea is to visually track an arm all the way from end to end and calculate the degrees rotation? It looks good, but the watch only runs with the gems off so I did that. Face down the amplitude seems to be ~360 which seems too high, but is there much less friction with the stones off? On its side (stone still off) it was 300.

Of course now I can't find the end stone to put it back in 🤦‍♂️.

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 Amplitude equals half of a full swing, 180 degrees is low.  Is 360 with the jewel in place or jewel removed as in above pictures? 

 Did you observe the hairspring for rubbing in face down position? since its when we expect the H/S to rub. 

 

 

 

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I understand that at the beginning the watch ran but did it badly. After disassembling and reassembling the end stones it doesn‘t run at all anymore. Did you know that the endstones have a flat and a domed side? The flat side is inwards. If the domed side happens to point to the pivot the balance has not enough end play and binds.

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Based on OP the watch ran        1-  oddly  

                                                     2-   was not keeping time

                                                     3-  came close to stopping face down

Case 3 was observed before disassembly.

Regds

 

 

 

 

 

 

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21 hours ago, MikeP said:

…Of course now I can't find the end stone to put it back in 🤦‍♂️.

OMG! 🥴 (I‘ve been there)

This tiny particle can jump into your hair or even nostril and disappear forever.

Good luck finding it!

Edited by Kalanag
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24 minutes ago, Kalanag said:

or even nostril and disappear forever

LOL, snorting cap jewels...another high.

In my short modern span of watchmaking (getting close to two years now), I have not lost a cap jewel.  They have gone flying on multiple occasions. However, I found that using a super bright large wide beam flashlight is extremely helpful in finding these things...even on carpet.

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Posted (edited)
7 hours ago, Kalanag said:

I understand that at the beginning the watch ran but did it badly. After disassembling and reassembling the end stones it doesn‘t run at all anymore. Did you know that the endstones have a flat and a domed side? The flat side is inwards. If the domed side happens to point to the pivot the balance has not enough end play and binds.

I didn't know this! To be honest I was just glad my eyes were good enough to see thing thing at all 🙂 Once I have both stones back in place, I'll try and make sure this is sorted so we can cross that off the list of potential issues.

4 hours ago, Nucejoe said:

This guy shows end shake.

https://youtu.be/gJwfOJ_TPt4

So when the lost end stones decides to find you, you have a chance to check the balance staff end shake. 

Regds

Thanks! I'll check this issue out as well. As below, I'm pretty sure the stones have gone to live with someone else because they're not here! I may be ressurecting this thread in a few days 🙂

3 hours ago, Kalanag said:

OMG! 🥴 (I‘ve been there)

This tiny particle can jump into your hair or even nostril and disappear forever.

Good luck finding it!

Lol "I'll fix my own watch, how hard could it be?" 😂 The stone may turn up in due course, but for the sake of my sanity crawling around on the floor I'm going to order a set too. I'll keep looking.

The ones I can't find are both one end stone, but also the holed jewel with the metal setting it is attached to. On cousins the part lists includes Inca 122.11 - Endstone which seems pretty self explanatory. Another option is Inca 111.09 - Jewel Hole, is this the holed jewel in a metal setting? These seem to come in packs of 5. There are also upper and lower blocks which presumably come with jewels but seems over the top to pay for all the metal surround and springs which I haven't managed to lose yet.

Thanks everyone for the support so far it's hugely appreciated.

Edited by MikeP
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Hi all, an update to how I'm getting on here. New jewels came in the post, so I've fitted a pair and they seems fine. Kalanag you were absolutely right that I had one of the stones in upside down, it no longer stops when I put the shock springs in. So that's at least one small thing solved.

I've dug out an old macro lens that I can use as a magnifier, and I've also bought a timegrapher. As was discussed above, I was able to get decent timing and amplitude face up, amplitude and timing dropped substantially face down. I've examined both pivots on the balance under magnification and I'm pretty sure they're both intact. However i've now lost any ability to regulate the watch on the timegrapher, maybe I damaged the spring? Or maybe I magnetised it. I took this photo below, it doesn't look as concentric as before, the coils on the left seem too close? On the time grapher it just looks like a snowstorm of dots all over the place.

I figured I'd try and solve this issue first before delving further into the face down problem.

 

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The alternative I guess is to replace it? I suppose if I need to replace it anyway, I can have a go at fixing it first. If it doesn't work easily enough I'll seek a replacement.

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1- You would want the coil centered.

2-Adjust the hairspring  to pass through the  mid-point of the gap in this " the etachron regulator stud", when the oscilator is at rest. You may need to turn the reg-stud a bit for such adjustment for isochronism which is best done with special tool. See DIY tools made by members, it basically a slot filed on a screwdriver blande to fit the stud head.

Good luck.

 

 

https://cdn.watchrepairtalk.com/monthly_2020_07/20200712_093708.jpg.d48b96ede20ea50904daaf1b682afbee.jpg

It can be used to turn the reg-stud with as well as pushing it out of the reg- arm.

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