Weird running eta 2836-2?????

[horologist]

Hello fellow members,

 

I would appreciate as much feedback as possible with an issue I am experiencing with a watch movement?

 

Prior to these eta parts and movements becoming obsolete, I replaced a damaged movement in a Rolex replica I purchased from Paul (Womart?) some years ago.

 

I purchased a new movement from a reputable seller which I have never had an issue with any previous movement I purchased before.  All exceeded my expectations!! I replaced this movement and set it all up to wear and it was running well within a range of 5-7 seconds per day. WOW that seemed great!!!  

 

UNTIL..... 

 

After a week to 10 days, I noticed it stopped at approximately 11.50.  I gave it a shake and it began running well again.  All good !!!  Then I noticed this to be a constant issue at approximately the same time repeatedly after a week to 10 days.  I then thought it might be the seconds hand out of line with the other hands.  I disassembled it and realigned them to make sure it wasn't the case, but again after a similar number of days, it showed the same pattern again.  Maybe not exactly at the same time as before but it again stopped at the same time as the previous occasion.

 

I noticed that the case clamps were not exactly holding it firmly enough, so I replaced them with firmer ones, making it nice and firm, making sure it wasn't the movement dislodging something while I was wearing it.  Again the same problem.!!

 

I was now clutching my straws and thought it could have been the DWO not realigned properly under the dial, so replaced it again to make sure it wasn't hitting against anything.  NO GO!!!!

 

I removed it to see if there were any dry areas in the jewel cups  including the train bridge.  I was beginning to think this mechanism was jinxed?  

 

Anyone had any similar experiences, I welcome as much information as possible as I have reached my  brainstorm limit??

Many thanks in advance

 

 

 

Edited June 19, 2020 by horologist
grammer

[Nanuq]

Paul and Womart, eh?  I remember having a watch from him that stopped the same time every day.  Tearing it apart I found a very nasty, very curly little black hair in the movement.  

 

Ewwwwwwwwwwwww.

[Timelord]

I  think OP is referring to the replaced mvt with that problem.

however it seems very strange that it stops a week or so later!  One would expect it to happen 12 or 24 hours later even if it grew hairs inside!

[Nanuq]

Magnetism?  How long would it take for every wheel, rotating at its own rate, to go around until their all their alignments (say, north to south) lined up again?  This would be like the world's gnarliest least-common-denominator problem.  Maybe when every magnetic field on every part aligns it's enough to stop the balance?

 

Or maybe it's as easy as a kink in the mainspring and as it unwinds it "catches" as it goes around?

[SSTEEL]

Check the forth wheel teeth.

[alligoat]

5 hours ago, SSTEEL said:

Check the forth wheel teeth.

I had the same problem a while back and it was one of the gears. It was an easy fix for the watchmaker and I had the movement serviced while it was apart- it had been like 12-13 years. 

[automatico]

"After a week to 10 days, I noticed it stopped at approximately 11.50."

 

Two hands gather up in the same spot at 1150 so check closely to see if the H and M hand are touching and make sure they are level.  If not the hands, it may have a speck in it somewhere...on something that turns once every 12 hours. 

Probably a speck because it ran Ok for a while then went haywire.

 

Old time repair guys/watch traders used to fix this type of problem by letting the movement 'spin down'.

'Spin down' = remove the balance and pallet fork, wind the watch up and let it 'spin down' a time or two.  Not recommended at all and not good for the movement but it slings the grit off the wheels.  

 

"Check the forth wheel teeth."

Good advice. 

You might have to check every wheel with a 10x loupe and Rodico. 

 

Things that turn every 24 hours (calendar stuff) do not cause much trouble...usually.

[horologist]

Thanks Gentlemen!  
every comment made is much appreciated and tonight I have it one my work bench with all the train wheels removed to see what is really the issue!  Before this I checked the hands and they all seemed to be clearing each other.  I would have expected it to stop at that same hour within the next  day. I removed  the  balance stop to keep it running while turning the hour hand,  I then removed the train bridge and  checked the seconds wheel teeth and they all seem to be intact.  I did notice that there was a bit of up and down play between the jewel and the pivot but it still was in the tolerance of making the escape wheel move.  Never noticed if this was ever the same with other movements I pulled apart.?  The bridge appears clean from any gunk with fresh oil in the jewel cups!  If else fails I will also clean the shock jewels which I am dreading as it is a novodiac instead of incabloc!  Otherwise as someone else said in a recent post the only sane answer is that this movement is female,  but even worse is that it gives Grief once every 10-14 days Instead of every 28 days

[horologist]

AN UPDATE !!!

 

OK Gentlemen,  I thought I would share with all of you something that had been rattling my brain for over the past week.

 

It seemed very strange that my movement would stop at approximately the same time every 7 to 10 days, which I still cannot work out why such a long period of time as opposed to every 12 or 24 hours after it makes a complete revolution.

 

Thanks to the clue offered by fellow member  SSTEEL and for other members suggestions to rule out, I focused my attention on the 4th wheel.  All the teeth were ok and the shaft and pivot seemed to be ok also.  I had the trainwheels out and checked each one of them and also the pivot jewels to make sure there was  no unwanted debris or dry oil causing issues there.  I also tried Automatico's suggestion of letting the wheels spin freely without the pallet and balance several times making sure wheels were sliding smoothly. I was still wondering what now until I noticed something not right with the trainbridge.  I have removed and replaced tranibridges many times but this one seemed to rock a little on the 4th wheel.  Did I not set it right?   No, I took one off another watch and checked both of them and surprise surprise, the bridge was slightly warped just where the fourth wheel sits.  Is this the problem?  I don't know but many of you with more experience on this will be able to tell if my theory is valid or not or it does not matter for the trainbridge to sit perfectly over the 4th wheel?  However upon assembling it again, without the automatic assembly, it was working well until I gave it a good shake and it stopped!!!!! I tweeked the 4th wheel and it started kicking again..   Maybe a fluke unless there is an underlying problem elsewhere.  All I can say is that definitely the trainbridge is not perfectly level when sitting on a flat surface as my other one.  A perfectly brand new eta movement!!!