Omega 1151 slowing down

[chonggwan]

Hello, my 1151 movement started to slow down. It's a day date Speedy 3520.50 from 1998, it was well treated and fully serviced by Omega in 2022. Since then it run about +2/-2 s/d, very accurately, but this year since the winter it started to slow down suddenly to -9 s/d and now to -11 s/d. Weather here isn't that cold (max. around 0), so I demagnetized the watch, but it keeps slowing down. PC timegrapher (via mic) shows 0 s/d, 0.0 m/s beat error with dial up, but starts to slow down when the watch is being moved and especially in the position with the crown down. There it gains around -10 s/d. What could be the reason for this behavior? I will bring it to the service, but don't know, whether to ask for the regulation only or a full checkup. There is no authorized Omega service center around, only a general service center for higher end watches like Omega, Rolex, etc.. Thank you!

 

[Bruce235]

It won't hurt to have it speed up a bit, since the service was recent. Have that watchmaker open it and adjust it on a timegrapher.