Blog - ONVA Watches Blog - ONVA Watches Mitchel Thompson
Summary:
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Many users experience when winding the watch, there is suddenly though occasionally, a terrible and loud clicking noise.
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Many users caution to be careful not to overwind the watch, as is possible with manually wound watches. Despite ensuring not to overwind the watch, some users reported the watch no longer running after the sharp noise.
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The cause of power loss is a riveting problem between the Great Wheel and its pinion. The barrel drives the great pinion under significant torque, but the rivet is weak, and the distribution of power to the rest of the gear train is disrupted when the rivet slips, creating a large power loss from the great pinion and great wheel.
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Secondarily, damage occurs between the sliding and winding pinions, on the Breguet teeth. This is the result of the sudden loss of tension between the two sets of teeth when winding, allowing them to disengage and slide across each other.
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I’m working on the (2801) version, though also exists is the updated caliber (H50). The issue is the same for both, likely more prevalent with the H50 because the spring holds higher torque for its longer power reserve, and the great wheel rivet can’t handle it. The wheel can’t even handle the lower torque of the 2801 mainspring.
Repair interventions:
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Replacement of all damaged components is required. A new sliding and winding pinion are essential.
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Replacement of the great wheel, though not visibly damaged, is necessary as it is the cause of the problem. The curious thing is if the new wheel will exhibit the same problem since the manufacturing process is why the component is failing, seen across many mass-produced examples.
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Sourcing of spare parts: only brand-authorized parts should be used, though I am running some experiments on brand-alternate part longevity.
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Alternatively, the existing great wheel may be repaired by tightening the rivet. This allows the wearer to keep authentic parts in their watch and will prevent the need for future replacement— as long as the new rivet is done correctly and tested.
