Beat Error in One Position

[dkpw]

I have been tending to a friend's DateJust which he has just inherited from his father. It's in very nice condition, it's an A Series (sold in 1999) 16200. I've added some links in and put it on the Weishi 1000 just to give him an indication of how it's running, and to advise him how to lay it overnight. As it came with all the original paperwork, we can tell it was last serviced in 2019 by the RSC.



I wonder if I may tap into the minds of those members with greater knowledge than mine, about a strange reading from the timegrapher? I caveat my question with an appreciation of the fact that the Weishi 1000 is not a professional machine, although I have found it to be useful checking my watches.

When I placed the watch on the timegrapher, in a very quiet room and gave each positional adjustment time to settle, I obtained these results:



As you can see the watch is running slightly fast. The amplitude is possibly a bit down in the horizontal positions but the flyer is the high beat error only in the 12 high position! While I show a rate of 6s/d the rate readings fluctuated wildly.

I ran the tests twice, having restarted the timegrapher and the results were similar. I checked other watches and these were measured as expected.

I am curious. What would cause a watch to display beat error in only one position? A drop? A bang?

I suspect I may recommend a service to my friend, as the 3135 could perform much better, but I would be grateful for any insights.

Thanks

David

[stefmcd]

I still think it's an anomaly. If that were the true beat error, it would surely send the daily accuracy way off more than a couple of seconds a day, no?

Sent from my CLT-L09 using TZ-UK mobile app

[dkpw]

I still think it's an anomaly. If that were the true beat error, it would surely send the daily accuracy way off more than a couple of seconds a day, no?

Thanks for the reply. My spreadsheet mimics the automated results from more expensive timegraphers so it's just an indication. Nonetheless I do find it strange that the machine reports such an errant result, just on that watch and in that one position. For example, I popped my MM300 on it and the results were consistent, in line with every other watch I've tested on it.

So I can't explain it.

[me32dc]

Was this 30 minutes after full wind?

If so then the amplitude is too low to get any real info from those results. Needs a service.

[dkpw]

Was this 30 minutes after full wind?

If so then the amplitude is too low to get any real info from those results. Needs a service.

Thank you, it was 10 hours after a full wind the night before.

[me32dc]

Have you got the results 30 mins after full wind also?
Does the error go or is it less nearer full power?

[Omegary]

As has been said redo your test half an hour to an hour after the watch has been wound fully. Ideally the average amplitude (X) should be no lower than 250º and hopefully more like 280º. The beat error should be no larger than +/- 0.5 in any position. Leave the watch for 24 hours and retest again checking that the amps are no lower the 200º. Looking at your readings after 10 hours I suspect you'll find it needs a service.

Oh and the cal.3135 is tested in 5 positions, the 12H test isn't part of Rolex's test when servicing, so the beat error is well within spec in 5 positions.

HTH

Gary

[dkpw]

As has been said redo your test half an hour to an hour after the watch has been wound fully. Ideally the average amplitude (X) should be no lower than 250º and hopefully more like 280º. The beat error should be no larger than +/- 0.5 in any position. Leave the watch for 24 hours and retest again checking that the amps are no lower the 200º. Looking at your readings after 10 hours I suspect you'll find it needs a service.

Oh and the cal.3135 is tested in 5 positions, the 12H test isn't part of Rolex's test when servicing, so the beat error is well within spec in 5 positions.

HTH

Gary

Thanks Gary and others.

The watch is now with it's new owner heading back down to Leeds, so is no longer available for further testing.

He's aware of the results and I've suggested he keep an eye on the timings. I also said that if it were mine, I'd be sending it in for a service, so that I could start my ownership afresh. As his wife is hankering for a retirement watch, I suspect he'll be killing two birds on one visit quite soon. :)

David

[Thewatchbloke]

The movement could be loose in the case (as in one or both of the case securing screws not as tight as they should be) which can cause a "echo" to be heard in various positions, this will throw the beat reading out.

Did you take the readings with the crown unscrewed? Having the crown screwed in will further isolate the mic from the movement and can have the same effect.

The above isn't normally an issue with Chinese timegraphers as they generate a "synthetic" signal but it does happen occasionally. It's more of a issue with timing machines that listen to the actual tic toc of the escapement and can generate a graph that can be analysed, for example like a Witschi Chronoscope.

[dkpw]

The movement could be loose in the case (as in one or both of the case securing screws not as tight as they should be) which can cause a "echo" to be heard in various positions, this will throw the beat reading out.

Did you take the readings with the crown unscrewed? Having the crown screwed in will further isolate the mic from the movement and can have the same effect.

The above isn't normally an issue with Chinese timegraphers as they generate a "synthetic" signal but it does happen occasionally. It's more of a issue with timing machines that listen to the actual tic toc of the escapement and can generate a graph that can be analysed, for example like a Witschi Chronoscope.

Thank you Duncan, and my apologies for not replying earlier. The crown was screwed in during the readings, which if I understand your post may indicate one the movement retaining screws may not be fully tightened.

I'll pass that onto the owner and see if a Leeds based AD can perform a short inspection and remedial action.

He has reported that the watch is running very well.