Strange jumping amplitude Rolex cal.1570

[Oyster]

Hi everyone !

I got a very strange problem after cleaning the movement 1570, the amplitude are good at 280~300 . 10 min later it drop around 130~170 and then it go back up to 280 again for a while, sometimes it completely stop. I did manually clean the jewel and all the cap jewel, the problem seem remain.Thanks for your time !

 

[Marc]

Assuming that all of the pivots right the way through from the main spring barrel to the balance are scrupulously clean and correctly lubricated, your main candidates are;

• bent or badly worn pivot
• damaged teeth
• damaged jewel

Any one of these (or any combination) anywhere in the train could cause the problem.

I would strip it back down again, inspect all of the jewels and all of the pivots and teeth under good magnification and see if I could spot anything amiss. If not then the only route is to reassemble in stages and check the free running of the train at each stage. If there is a problem with intermittent power loss in the train then it will eventually come to light.

The only other potential cause that I can think of would be a distorted main spring intermittently jamming in the barrel. You also need to check the main spring arbor in the barrel, and in the main plate and bridge pivots for freedom.

[Oyster]

Will try that, thank you !

[Oyster]

Update, I tried everything and inspect every parts, non are damage, but after I remove the calendar driving wheel is run good ! , so I put it back to test, and the watch got amplitude jump again. I noticed that if I tight the screw on the calendar driving wheel it cause this problem.

[Marc]

Is it possible that the wrong screw has been used on the calendar wheel?

Thinking out loud is it possible that too long a screw is projecting too far out the other side of the plate and just impinging on the spokesman of a wheel enough to take power but not stop the train. Then when the spoke clears the screw amplitude is restored until the next spoke.