HowTo: Service a Jaeger LeCoultre Atmos clock (official manual)

Some time ago I bought the inventory of a deceased watchmaker, it took me about three days to sort everything out into different categories like tools, parts (watches, pocket watches, clocks and stopwatches). It is always a lot of fun to see what treasures you might uncover, and one of these is an official service manual for a Jaeger LeCoultre Atmos clock.

The Atmos clock is a small mechanical wonder, you don’t have to wind it, it literally winds itself. It contains a gas that shrinks and expands on only the slightest of temperature change. If the temperature changes one degree Celsius it stores enough mechanical winding to run for two days. It can run without human interaction for decades and might be the closest thing to a perpetuum mobile you have ever seen. To achieve this a heavy pendulum rotates back and forth in exactly one minute which is a pleasure to look at.

This document describes servicing a caliber 528 but I believe that it can provide useful information about others as well. Sadly it is in German, but a quick Google Translate should help you on your way on your own language.



Disclaimer: Please understand, servicing an Atmos clock is not an easy thing to do, so if you are not in any way proficient with servicing clocks please consider asking a local watchmaker or clockmaker if he/she has actual knowledge about this (point them to this document if you want) or just contact a Jaeger LeCoultre authorized dealer (

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