Intriguing ETA 2678 issue

[matabog]

lol

that tip is like the nail on your finger!  It's the one that counts!

Without the canon pinion in place, the minute wheel turns freely

[Chopin]

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 ?

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 April 25, 2019 by Chopin

[Nucejoe]

This guy didn,t pay close attention to OH's advicehe hardly got a hair left.

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

[Chopin]

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 April 25, 2019 by Chopin

[HSL]

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.

[Chopin]

Photo of the screw and plate.

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.

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 April 26, 2019 by Chopin

[Nucejoe]

The min train screw.

Return bar too, is a culprit on those .

Edited April 26, 2019 by Nucejoe
Imadeguate

[Nucejoe]

 

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 ?

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.

[HSL]

1 hour ago, Chopin said:

Photo of the screw and plate.

Yes they look okay as I told you before..

[HSL]

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.

[HSL]

The effect you describe has to do with the design of the stem, you shoud see a slight curl on the top of it instead of a straight one.