My Hamilton Model 21, purchased October 2021 (it was advertised to have had a complete service prior to the sale) ran continuously and perfectly until now. It just stopped one day although fully wound. After restarting it ran for a day or so, then stopped again. When I opened it up and watched, the escapement seems to work properly, but the balance amplitude just decays until the impulse no longer triggers and it dies. The jewels look good. Does anyone have an idea what’s going on?
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