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Chopin

Intriguing ETA 2678 issue

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Hello everyone, hope you're doing great!

I have a watch with an ETA 2678 automatic movement. Everything functions correctly but there seems to be a small issue.

When adjusting the hands, at some point, the crown seems to slip just a bit and I think that I can hear a click or two (like something is slipping inside).

It doesn't happen in the same spot from what I can see. It happens once ever 4-5 crown revolutions, maybe more... When it happens the crown itself slips a bit. If I rotate it counter clockwise it doesn't do the same thing.

Also, if I rotate it backwards and then forward again it'll do the same thing in the same area/position.

I'm only posting because I don't really want to take this apart, or at least maybe I can just remove some of the parts and not the whole thing.

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What I'm confused about is the fact that with all the parts in place it only slips when adjusting the hands clockwise. If I adjust them counter-clockwise it works fine.

I'll try loosening the canon pinion... Out of curiosity what is the correct way to loosen such a canon pinion ?

Are you supposed to slightly pull the 2 tabs that hold the tube outwards or what ?

images-3.jpg

Also I still get the impression that the small steel gear might not engage properly with the minute wheel due to pivoting just slightly. Not sure.

Edited by Chopin

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This guy didn,t pay close attention to OH's advice:pulling-hair-out:he hardly got a hair left.

Screw for min tran bridge is wrong ons, soon new part gets worn out  like what you now got.

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How come the screw is wrong ? How does the screw influence all this ?

What should I be looking at exactly ? How does one know that it's wrong ?

PS: that little plate (that covers the parts) is flat from what I can tell.

Edited by Chopin

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lol ..no need to rip your hair off

Unfortunately I didn't have the ETA 2678 at home right now but as happens I got a few ETA 2671 whitch is the same movement except without the day indicator.
I guess the screw is the one I have circled in yellow , on these small movements they actually looks like this when they come brand new.
What you should check is if the day/date dials is moving smooth, if they dont then it might cause the stress to break a tooth on the wheel.
While your at it check the yoke action is nice and crisp, if it's weak the sliding pinion might just tuch the tips and that will break the teeth too.
Since you say it works when you take the cannon pinion out it might just be in the progress to change date/day and just got stuck.

IMG_20190425_195454.jpg

IMG_20190425_195544.jpg

IMG_20190425_195742.jpg

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Photo of the screw and plate.

IMG-8144.jpg

It seems like this circled part below is moving just a bit downwards (talking about the tip that holds the gear not the entire part) but only when the hands are adjusted clockwise and only when it reaches the borken tip does the gear that it holds start to slip and not engage with the minute wheel.

IMG-8145.jpg

Also, strangely, if I take a few parts out and put them back it can run well for a few rotations but then something goes bad and the issue begins to repeat. It's as if the canon pinion is smoother and then it becomes a bit stiffer...

Edited by Chopin

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What I'm confused about is the fact that with all the parts in place it only slips when adjusting the hands clockwise. If I adjust them counter-clockwise it works fine.

I'll try loosening the canon pinion... Out of curiosity what is the correct way to loosen such a canon pinion ?

Are you supposed to slightly pull the 2 tabs that hold the tube outwards or what ?

images-3.jpg

Also I still get the impression that the small steel gear might not engage properly with the minute wheel due to pivoting just slightly. Not sure.

You shouldn,t pull the two tabs , oil the canon pinion groove that sits between the two tabs, instead.

Clean and lube the date jumper. The min train and date train + date jumper+ day change, should altogether turn nice. Excess resistance and unlevel min train cover/ bridge will cause one gear to ride over the pinion of the other, that has been the case here. I think Mark put some oil on top of min gear in between min gear and its cover.

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But the yoke seems to be inan aqward position when the stem is pulled away..

It should look something like this, the yoke should push the sliding pinion down.

IMG_20190426_160022.jpg

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