Just for fun, here's a photo showing the standard Valjoux 23 (on the left), next to a Valjoux 230 (on the right). The Valjoux 230 is the flyback movement used in the Heuer Bundeswehr chronograph. Three differences between the Valjoux 23 and the Valjoux 230 are noticeable immediately:- The red arrows on the Valjoux 230 point to the lever that allows disengagement of the drive, so that the chronograph can be reset, without stopping the chronograph.
- The additional screw on the reset lever (circled in blue) pushes this lever down, to disengage the drive.
- The reset lever on the Valjoux 23 has a lip or tab (circled in green) that goes to the column wheel, to prevent reset while the chronograph is running; there is no such lip on the Valjoux 230, as "flyback" means that the chronograph can be reset while the chronograph is running.
Some refer to "flyback" as instant reset, as the chronograph can be reset and restarted, in an instant.
Jeff
