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Problem with Speedmaster No861 moonwatch.

  1. buddyboy Apr 12, 2021

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    Hi, I have a problem with my Omega, If I use the Second-hand function and forget to cancel it it runs down the system quite quickly which obviously results in the watch stopping, Is this normal or is it a fault? Regards David.
     
  2. Dedalus05 Apr 12, 2021

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    I would expect the power reserve to run down quicker when the chronograph is engaged compared to it not engaged, but how wuickly are we talking about?

    Also, welcome to the forum.
     
  3. Archer Omega Qualified Watchmaker Apr 12, 2021

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    The power reserve doesn't change, so the mainspring unwinds at a constant rate no matter if the chronograph is running or not. However the watch will stop sooner with the added load, so a shorter run time of a few hours is normal.

    It really depends on exactly what "quite quickly" means. When was your watch last serviced?
     
  4. befobe Apr 12, 2021

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    Just a beginner question, for @Archer I guess:... If the "added load" makes a "shorter run time", why can't we say that the "power" does "change" when the chrono is on?
     
  5. Motik Apr 12, 2021

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    As Archer explained the power reserve is the same, as the mainspring will take the exact same time to unwind.

    What changes is the minimum power needed to move the hands, because, with the chronograph on, you now have more weight to move and friction to overcome each time the escapement opens. And the watch will stop, not when the power reserve is exhausted, but when it is below the new, higher, minimum needed to move the movement and the hands.

    In fact, if you then disengage the chronograph, the watch will probably start running again for a while, showing clearly that the power reserve was not exhausted. It was just too low for the increased load you were putting on it, but ok for a lighter load.
     
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  6. Dan S Apr 12, 2021

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    How quickly? In other words, if you wind the watch fully, and then let it run with the chronograph going, how long does it run before stopping, approximately?
     
  7. buddyboy Apr 13, 2021

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    Hi Dan, From a full wind at 06 00 in the morning, If I engage the second hand at 22 00 and forget to cancel the watch stops at approx' 03 00
     
  8. buddyboy Apr 16, 2021

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    Hi, Thanks for the reply, On a full wind and all systems engaged, The Chrono' Stops after 23 hours, The main watch carries on and stops after 52 hours, Any help? Regards David.
     
  9. buddyboy Apr 16, 2021

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    Quite some time ago, I live in Fuengirola Spain and am not sure of a qualified company around here.
     
  10. Foo2rama Keeps his worms in a ball instead of a can. Apr 16, 2021

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    Because the power reserve did not change, just the available torque.

    So fully wind a watch and it makes it 30 hours with the chrono off

    Fully wind a watch and start it with the chrono it makes it 25 hours. Turn off the chrono and it will get another 5 hours.

    The issue is the mainspring in a wound down state does not have enough torque to overcome the friction of the chrono and rest of the movement. Turn off the chrono and reduce the torque needed and it can drive the rest of the movement.
     
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  11. Foo2rama Keeps his worms in a ball instead of a can. Apr 16, 2021

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    That seems a little extreme, when was the last time the watch was serviced? Sounds like something is adding a lot of drag in the chronograph part of the movement when engaged.
     
  12. befobe Apr 17, 2021

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    Oooo that's smart. Thanks, perfectly clear.
     
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  13. buddyboy Apr 17, 2021

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    Some time ago, 5 or 6 years, I live in Fuengirola Spain and am not sure of a dealership here, I'm a bit loath to mail it to UK in case it gets lost in transit.