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Quartz watch regulation – Very geeky

  1. Deafboy His Holiness Puer Surdus May 10, 2016

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    I would like to share my method for measuring and regulating a recently received Omega Seamaster « Titane » (a.k.a. Polaris).

    This much maligned 1980’s Gerald Genta design has a unique gold inlay titanium case. The dial is of a dark matte gray with white minute markers and cabochon lume hour markers. It is pretty much the only date dial design that I find attractive. My watch has the reference (TR 396.1121) which dates from 1988, and came with either the 1441 or 1438 movement. I got lucky because I obtained the 1441, which is a high grade caliber using a thermally compensated quartz crystal. This movement uses a second quartz crystal as temperature sensor and is capable of 2 seconds/year accuracy. It has two switches on the movement's electrical circuit board that permits adjustments in increments of 0.33 seconds/month (i.e. 4 seconds/year).

    Being of a scientific nature I wanted to analyze the accuracy of this watch. I don’t have dedicated watch instrumentation but I do have a Hewlett-Packard 5335A timer (well… who doesn’t?). It has two channels so I used one channel for the watch seconds electrical signal from the movement’s circuit (see open watch picture) and compared it to a GPS signal (which provides an accurate 1 pulse per second signal - pps) on the other channel.

    IMG_5256.JPG

    IMG_5258.JPG

    The figure below shows three curves of results. The one traced in Blue is the watch’s error compared to the reference 1 pps signal. We see that the movement uses a variant of the Inhibition that @Archer described in a recent post. Every few minutes the watch makes adjustments to the rate based on the temperature and regulation setting. The deviation from perfect time is a loss of 2.5 milliseconds in the hour of measurement, which corresponds to -23.2 seconds/year. After tapping the switches on the movement several times and obtained Red curve, which has a slope of -3.2 seconds/year. One final adjustment I obtained -1.2 s/year over the hour time span (Green). As a sanity check I did a longer test (60 hours) to see if the accuracy would be maintained. The results are shown in last figure, where I obtained a deviation of 6 ms or +1 second/year. During this period the ambient temperature varied from 17 to 29 degrees Celsius.

    Not bad for a 30 year old movement! :cool:

    Michel


    3curves.jpg
    Long_term.jpg
     
    Edited May 11, 2016
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  2. JimInOz Melbourne Australia May 10, 2016

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    Thanks for an interesting diversion from recent subjects.

    :thumbsup:
     
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  3. oddboy Zero to Grail+2998 In Six Months May 10, 2016

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    that's awesome! so nice to see some ancient tech working together to produce such an impressive result.

    bet you can't do that with an Apple watch (though the counter argument is, I guess, that you don't have to).

    great post, thanks for sharing with us.
     
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  4. Deafboy His Holiness Puer Surdus May 10, 2016

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    Both the watch and the HP timer are from the 1980's. Ancient tech? :confused:
     
  5. oddboy Zero to Grail+2998 In Six Months May 10, 2016

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    that was well into the last century!

    :)

    I'm just making light of this hobby of ours... no harm intended.
     
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  6. wsfarrell May 11, 2016

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    1 second a year? YOW!!!
     
  7. primabaleron May 11, 2016

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    [​IMG]
     
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  8. Kobus May 11, 2016

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    crazy

    Love it.
     
  9. Jones in LA Isofrane hoarder. May 11, 2016

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    Cool stuff! Thanks for posting this!
     
  10. Birky101 May 11, 2016

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    Hi when you say 'tapping the switches on the movement' can you please explain what you mean as I would like to adjust my Omega[​IMG]

    Sent from my Harrier Tab from EE using Tapatalk
     
  11. Deafboy His Holiness Puer Surdus May 11, 2016

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    If you look closely at the picture of my watch, there is an inscription that says "1 imp = 0.33 s/month" with + and - signs next the the switches. From the looks of your movement, it doesn't appear to have such inscriptions, which leads me to believe that it is not adjustable using switches. Perhaps it is adjusted at the factory but a watchmaker doesn't have that option. Maybe Al can chime in (@Archer).

    Which movement do you have?
     
    Edited May 11, 2016
  12. Deafboy His Holiness Puer Surdus Apr 6, 2017

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    A bit of an update.

    I'm quite amazed by the performance of this watch. I set the time in early November 2016. In the meantime I only change the date and hours (which you can do on this watch without affecting minutes and seconds) to account for daylight savings time and odd months. Well, 5 months later (13 million seconds later...) it is still within 1 second of perfect time. For a portable timepiece that is untethered (no link to GPS time like an iPhone or Casio Wave Ceptor) it is remarkable.

    S0019136.JPG
     
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  13. Archer Omega Qualified Watchmaker Apr 6, 2017

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    How much was it worn in that time?
     
  14. Deafboy His Holiness Puer Surdus Apr 6, 2017

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    Not much (I have 10 vintages watches after all...), maybe 10 days, but I'm wearing it today! :D
     
  15. Archer Omega Qualified Watchmaker Apr 6, 2017

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    Temperature stability is key to quartz accuracy, so the constant temperatures over this time would have certainly helped. Taking it on and off each day would likely have created more variation if it had been a daily wearer.
     
  16. Mouse_at_Large still immune to Speedmaster attraction Apr 6, 2017

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    Kudos for taking on this research and keeping us up to date. Extra kudos for the love of Polaris :thumbsup:
     
  17. adi4 Apr 6, 2017

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    Would be really interesting to see how it performs if you wear it consistently for 1 month and take it off at night. Would also be nice to track the ambient temperature while it's at rest too for the full picture. Looks like very nice performance so far though!

    I thought the 1441 movements were spec'd to +/- 10 sec/year and not 2 though? Still, very nice and I love seeing the adjustable HAQ's still being able to perform so well.
     
  18. Archer Omega Qualified Watchmaker Apr 6, 2017

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    Capability is one thing, but tolerances from Omega state 0.8 seconds per month is allowed:

    Checking the rate

    Check the rate in the following manner :
    – Set the watch to exact time.
    – Stock the watch for a duration of about 1 month.
    – Check the watch by the same time reference which was used for the time setting.
    – Calculate the rate M in sec/month.

    If M > 0.8 sec/month, correct the rate.
    If M < 0.8 sec/month, no need to correct the rate.


    Cheers, Al
     
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  19. adi4 Apr 6, 2017

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    Thanks Al, just wondering if you do that regularly for HAQ's or if it's something that would be done only if the owner requests (and is ok with extending the service time to 1 month).
     
  20. Deafboy His Holiness Puer Surdus Apr 6, 2017

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    In fact I did exactly that. I checked regularly with the NIST website and the two always overlapped to within the second.

    Ok, let's try that for fun. One month daily wearer.

    Maybe it is specified to the +/- 10 sec/year, but one can adjust the rate in increments of 0.33 s/month. Either way, it's still very good.
     
    Edited May 4, 2017
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