ETA 2836-2 Auto Mechanism Issue

[Dico]

Hello All,

I just serviced an ETA 2836-2 which runs flawlessly up until the auto mechanism is put back on. Without the auto mechanism it runs almost a full 36 hours when fully wound but once the auto mechanism is on it stops intermittently every few hours even when its sitting still. The mechanism is seated correctly and I verified nothing is interfering with the balance. Any thoughts on what can be causing this?

[clockboy]

Is the rotor bearing OK. Just wondering if it has a bit of a wobble & is then fowling somewhere. 

[Dico]

Thanks for the response clockboy! The rotor bearing is ok I even changed out rotors just to be sure that wasn't the cause. Any other ideas?

[transporter]

When you place the auto wind bridge back on do you rotate the wheels slightly so they all line up and mesh before you screw the bridge down? I know you said everything is inline but I've been there before and you cannot see the wood for the trees so to speak

[rogart63]

How did you service the reverse wheels . Usually that is the problem. Check if the rotor moves when you handwind the movement. If they do you need to clean the reverse wheel. Or change them. if they are worn. 

[frenchie]

Reverser wheels have my vote as well, if you didn't replace them.

[Dico]

Thanks for all the help. I have concluded that it only happens when the actual rotor is put on, and verified the rotor isn't rubbing against anything. Can this still be the reverser wheels?

[FlyingWatchmaker]

Yup, this is a classic eta issue.. firstly, the rotor and reversing wheels must be as clean as physically possible..

the rotor bearing requires a very small drop of oil on 1 or 2 of the balls

each reversing wheel requires the smallest possible oil on the tip of each pawl where it contacts the mating locking surface inside the wheel, and possibly a miniscule drop between the wheel arbor and the free running wheel of the reverser (hard to describe, and sometimes this doesnt work)

I use 9010 to lubricate these, after epilaming, to make sure the oil doesn't sod off to places I don't want it ;-)

if after doing this, demagnetising, and it still makes the rotor "propellor", clean them, repeat the process and don't be surprised if you need to do it a 3rd time ;-)

if you do make it to the 3rd time, the reversing wheel may need replacing..

Tom

[clockboy]

ETA developed this lub just for reversing wheels
ETA Lubeta V105.

I have never used it but have read it is very good and easy to use.

[FlyingWatchmaker]

The Lubeta is meant to work well, unfortunately getting a single bottle of it into Australia is prohibitively expensive ($4-500) due to hazardous material charges.. the 9010 is what is used at the swatch group service centre here, and more easily available.

The lubeta does also leave a white non-uniform residue over the entire part, so isn't appropriate for watches with a visible movement.

Tom

[Dico]

Hi All,

So over the past 2 weeks or so I've tried cleaning and oiling the auto mechanism 3 different times...that didn't work

Change out the rotor completely to a brand new one....that didn't work

Change the whole auto mechanism including rotor to a new one....and that didn't work

I'm at a loss here....is there anything else that can be causing this god forsaken watch to stop ONLY when an auto mechanism is re-attached to it??

[SSTEEL]

Have you changed the main spring barrel at all?

[FlyingWatchmaker]

Oops, I just realized you meant the main movement was stopping, I was just thinking you hadn't got the auto winding properly...

Check anywhere there might be a pivot being interfered with, (centre seconds is a common one if the second hand has been put on without supporting the jewel), that the train bridge is flat, and not being pressed on by the auto bridge, also where the auto transmission wheel post goes into the barrel bridge, there's an opportunity for pressure...

Another one that just came to mind, make sure the auto bridge isn't pressing on the regulator on the balance cock...

Tom

[SSTEEL]

Also make sure you are using the correct screws in the right places, a slightly long incorrect screw can cause these kind of issues.

[clockboy]

If the watch still runs for 36 hours without the auto then it is still the auto or auto assembly that is the issue. I have read many times that most auto wheels run better not being lubricated just cleaned. ETA developed Lubeta to address this but I would be very surprised if this was the issue. I would say it is a assembly issue. Is it possible to a post a pic or even better a short vid of the movement running and the auto rotation.

[Dico]

Thank you for all the great responses. Taking the advice of clockboy I’ve included 2 short videos so you all can see the movement, screws and how things are seated. In this condition shown in the video, the watch runs flawlessly.

As soon as the rotor is placed on it again it stops within 12 hours. I’ll post another video with the rotor attached. I’ve changed the whole auto assembly to a new one so I don’t think the issue is there. It must be something else. Could the mainspring barrel cause this?

7CAE1615-DF00-49CD-B7F8-B75405400A15.MOV

BD73A76B-151D-4C8C-924E-67262647F793.MOV

[SSTEEL]

7CAE1615-DF00-49CD-B7F8-B75405400A15_MOV by S STEEL, on Flickr

Double check this gear, the two jewels of this gear should be visible from the rear, if not, you may have this gear fitted the wrong way.

[clockboy]

I think SSteal could have found the fault. When the rotor is attached do the reversing wheels move freely in both directions.

[Dico]

Comparing to other 2836-2 that I have the reversing wheels look to be installed the same way. The seem to move freely in both directions. I’m attaching close up photos and the video now with rotor attached. Thanks again for all the help.

C5674B11-F4F6-45FA-BE4A-47B515447BC9.MOV

[Dico]

[Dico]

Hi everyone

Still having the same issue here. I noticed after the last video I posted that even after winding a few times the balance does not start moving. In fact I have to shake the watch to get it going and then it’s fine as long as rotor is off. Can that have anything to do with the stopping issue I’m encountering? Issue with the barrel?

[Dico]

Hi All,

I'm still troubleshooting here. Noticed when it stops its always at the 51 or 52 second mark. The hours in between are random could be as little as 10 mins or as much as 12 hours - but always stops at about the same seconds mark. What does this mean??

[jdm]

3 hours ago, Dico said:

What does this mean?

That there is an issue with the second hand or wheel.