V I I I . H o w to detect quickly the cause
of a functional defect
of the chronograph mechanism
Detecting the stopping
Check whether the coupling wheel drives the chronograph
wheel.
If so, delicately sepárate the coupling clutch so as to provoke disgearing
between the coupling wheel and the chronograph wheel.
- If the balance starts running again, the stopping is due to the chrono-
graph mechanism.
Stopping due to the chronograph mechanism
The chronograph hand is stopped between the divisions 58 and 60 of the
dial:
- Slightly sepárate the minute recording jumper from its wheel. If the
watch starts running again the defect may result f r o m :
A Overtension of the jumper spring for the minute recording jumper.
B Defective stateof theworking surfaces of the minute recording jumper.
C Lack of freedom of the minute recording jumper.
D Lack of freedom of the minute recording wheel caused by:
D1 Bad state of the pivots. (They must not be lubricated.)
- Lack of freedom of the minute recording hand which rubs on the dial.
E Lack of freedom of the sliding gear wheel.
E1 (The pivots must not be lubricated.)
F Depth of the chronograph runner finger with the sliding gear wheel
too shallow (butting).
- If the cause of stopping could not be eliminated, delicately sepárate
the coupling clutch.
T h e watch starts running again, the defect can be rmputed t o :
G Lack of freedom of the chronograph runner produced by:
Lack of cleanliness of the center-wheel tube.
G1 Tensión of the friction spring too high.
- Crushing of the tube of the chronograph hand that comes into contact
with the inner part of the center-wheel tube.
G2 Bad state of the toothing of the driving-wheel.
G3 Bad state of the toothing of the coupling-wheel.
G4 Bad state of the toothing of the chronograph runner.
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