WS 19: Servicing a SEIKO Chronograph 6138

All screwed parts are now removed from the chrono plate covering the right upper half o the movement. SEIKO made a clever compromise riveting some of the levers to this plate. Also some other complicated wheel-lever combinations are riveted together. This makes it a lot easier to service the movement!
In the center of the movement is the chrono wheel and vertical clutch clearly visible! This is the heart of this chronograph movement. When the chronograph pushers are pressed, the clutch engages (is lowered) and the chronograph starts running.
Before we go into more details regarding the vertical clutch, let us have a look at the big balance wheel in a 6138.

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