A. Lange & Söhne Datograph Service & Repair

Key Points from the Discussion

• Some watches, particularly those with Swiss Lever escapements like the Datograph, are generally self-starting. However, if the escapement and balance wheel stop in a specific position, the watch might require a gentle nudge or a stronger mainspring impulse to restart.
• Magnetization can cause erratic behavior, including a watch stopping or gaining time due to the balance wheel banking. Demagnetizing the watch can resolve such issues.
• Several factors can prevent a watch from running after a long period, including old oils, magnetism, and extreme temperature changes. Regular wear or winding can help maintain a watch's fitness.
• The original author speculates that the tension from a full wind, combined with the watch sitting, might have loosened a stuck gear, allowing the movement to restart. This was a unique experience for them after many years of watch ownership.
• While the watch may have restarted, it's advisable to have a Lange service center inspect it to ensure proper lubrication and address any underlying issues, especially for a valuable timepiece like a Datograph.
• If a watch doesn't start immediately after winding, a gentle rotation on a horizontal plane can often encourage the movement to begin, preventing unnecessary concern.
• To check for magnetization, one can use smartphone apps like Lepsi (if available) that utilize the phone's magnetometer, or simply place a compass near the watch to observe if the needle spins.