Class El Primero Chrono Second Hand Stopped by Minute Hand
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Thread: Class El Primero Chrono Second Hand Stopped by Minute Hand

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  1. #1
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    Question Class El Primero Chrono Second Hand Stopped by Minute Hand

    The pre-owned Class El Primero (02.0500.400) I purchased finally arrived yesterday. This watch is amazing and so far keeps good time.

    But I've noticed an unusual problem. While the minute hand is between the 7 and 10 position, if I start the chronograph, the chrono second hand would stop at where the minute hand is, thus bringing the entire watch to a stop. If I try to adjust time when this happens, I can see the minute hand 'dragging' the chrono second hand with it, again between the 7 and 10 position.

    My guess is the hands are not seated properly. If so, is it costly to get it fixed?

    I'm also in the process of contacting the seller right now to find out what options are available.
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  2. #2
    Zenith Forum Co-moderator
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    It should not be expensive - after all, there is nothing wrong with the movement, it's just a matter of correcting the interplay between the hands. They might have to be bent ever so slightly, though and this risks damage to the lume.

    Hartmut Richter
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  3. #3
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    Thank you, Hartmut!

    Do you recommend that I take it to an AD? Or just any reputable watchmaker with Zenith experience?

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  5. #4
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    So, as of yesterday, while 'monitoring' the chronograph function, I started noticing that sometimes the chronograph doesn't start unless I tap on the watch a few times. Tapping doesn't always work, but stopping and starting the chronograph manually would restart the chronograph in those instances. When the chronograph second hand stops, the whole watch stops.

    This happens even when the chronograph second hand is nowhere close to the watch's minute hand.

    Is it possible that this is caused by the hands not seated properly? Or can this be a problem with the movement itself?

    As long as the chronograph isn't stopping the watch completely, the watch continues to keep good time.

    I've also contacted the seller and they are giving me the option to return the watch. Should I return it or go find a watchmaker and have the hands re-set?

  6. #5
    Zenith Forum Co-moderator
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    The first question is: if the chronograph seconds doesn't move when you start the chronograph, does the chronograph mechanism inside engage and work properly? If so, the chrono seconds hand is now loose (probably due to the antics of dragging it along with the minute hand).

    If the chrono is engaged and the chrono seconds catches on the minute hand, this will naturally cause the entire watch to stop: the resistance goes all the way back into the movement and stops the balance. The same goes for a situation in which the minute hand catches on the chrono seconds hand - if the chrono seconds is still tightly attached to its pivot! One crucial question is: what is the balance amplitude is there is no foul play between the hands? If it has dropped, there is more wrong with the watch than just the hands. In which case, my advice would actually be to return the watch or make sure that a decent full service is done (preferably by Zenith) at the expense of the vendor.

    Hartmut Richter

  7. #6
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    Thank you very much, Hartmut, for the explanation!

    I do see the 2 wheels engage when I start the chronograph. When the chrono second hand stops on its own, those 2 wheels stop, and then the balance would stop too in a second or so.

    I'm not sure whether or not the watch had been dropped before I received it a few days ago. It's a pre-owned and shipped from Japan. No damage to the package and the watch was securely packed in its own box.

    If the balance amplitude is bad, while the chronograph is not activate, would the watch be able to keep good time, like +- 2 or 3 seconds a day? The reason I ask is because, unless I take it to a watchmaker, I don't have the right tool to test it.

    By the way, how many turns of the crown would fully wind the watch? Unlike my other automatic watches, I do not hear any clicking at all regardless of how many times I've turned the crown.

    Any guess on what a full service by Zenith would cost?

  8. #7
    Zenith Forum Co-moderator
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    The Zenith service costs are on their website. Please be aware that if you send the watch in, they give you a quote and you refuse, they will still charge you around 100 Swiss Francs for the pleasure of having it looked at.

    If the balance amplitude is low, you may still get decent rates but in particular the consisteny between positions will suffer. But in any case, it is indicative of the fact that the watch needs a service (weak mainspring, stiff balance spring or most likely cruddy movement) and leaving it will risk damage.

    A watchmaker with the right tool - an electronic timing machine - will be able to tell you the balance amplitude in an instant and most will do that little service without charge.

    Good luck!

    Hartmut Richter

  9. #8
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    Thanks again, Hartmut!

    I ended up returning the watch, then a few days ago I found another one 02.0500.400 from a seller in the U.S. According to the seller, the accuracy of the watch is +6 sec/day. I think that's within the normal limit of a non-COSC watch. This seller has an in-store watchmaker who can try to improve the watch's accuracy, but I'm not sure if it'll make much difference.

    Should I ask him to give it a try?

  10. #9
    Zenith Forum Co-moderator
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    I would do so. The COSC specifications are between -4 and +6 seconds/day for the ordinary deviation but what is far more important is how steady the watch performs. If it's -10/day, every day, it should just take a turn of the screw to get it to 0/day. If it's -4 one day and +6 the next, then this is acceptable but a fair pain since that represents a maximum difference between two daily rates of 10 seconds and the movement can do much better than that. The maximum difference should be <5 seconds a day.

    Hartmut Richter

  11. #10
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    Re: Class El Primero Chrono Second Hand Stopped by Minute Hand

    Thank you, Hartmut, for the advice!

    I've e-mailed the seller about improving the watch's accuracy. Will keep you posted on the result.

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