Weird timegrapher results

[Bopmd]

Hello. Sorry if this question already has been answered, but I didn't know what to look for. 

I recently cleaned a certina 28-10 and it was keeping excellent time. The next morning I noticed it had lost a lot of time (about 40 seconds) and I put it on a timegrapher. The accuracy went from +4 to - 40.. I then re-regulated it and a few hours went. I then checked again and thw same problem had occurred. Only this time it had only gone from +5 to - 20. 

 

I also noticed that sometimes the amplitude drops to about 170 and the beat error goes up to 10ms for a few seconds and then returning to normal again. You can see that in the picture. This has happened several times. What could be the cause of all this?

Edited May 26, 2020 by Bopmd
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[spectre6000]

Is this in a particular position? I think (and I'm still pretty new at this) it looks like the balance or hair spring are hitting/rubbing on something. For it to register as beat error, I imagine the timegrapher would have to have seen a fairly sharp noise, so I'd suspect hitting rather than rubbing. However, I think hitting would be more likely to make it run fast than slow, whereas rubbing would be more likely to slow it down. This is where it'd be nice if the timegrapher gave you the actual audio/trace rather than a beep/click. Check end play, and remove the balance cock/bridge to see if there are any tattle tale marks where it's hitting/rubbing.

[watchweasol]

Hi  does this problem occur ia singular position  ie  Dial up or Dial down or is it in all positions,  ?.       

[DavidMasters]

I had an experience recently where a watch was experiencing similar problems. After MUCH looking I finally found the lower hole where barrel arbor rests was oval and barrel had lots of play. I happen to have a old movement so I switched the parts to the old movement plate and problem was resolved. So, I guess my reply is to see if barrel arbor upper/lower holes are worn and causing excess play and wobble.

Regards

[JohnR725]

On 5/26/2020 at 7:06 AM, Bopmd said:

I recently cleaned a certina 28-10 and it was keeping excellent time

We need a clear clarification of what cleaned means? In other words did you fully disassemble it did you change the Mainspring?

At 170° everything gets magnified so don't worry about the beat error it's only because the amplitude crashed and burned.

I assume the watch is currently cased up?

 

 

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Certina_28_10

 

[Bopmd]

On 5/26/2020 at 7:22 PM, spectre6000 said:

 

Everything seems to be fine now. The accuracy is not receding anymore and the rest seems to have stopped. Sorry for the late replies and thank you for yours