... this beautiful post and exchange of information between you and your knowledgeable watchmaker.
Not being myself a PP collector (though definitively I´m an admirer of the brand) and not having much technical knowledge about movements, I enjoyed so much reading the comments of the watchmaker as he dismantled your watch for service, and explained the features of this marvelous movment, and the problems he found in it.
I´m sure he will be able to restore it to its full functioning grandeur and ship it again to you to enjoy.
It is incredible how much care PP dispenses to parts of its movement which will never be seen by any other than the original assembler and in any case, the watchmaker who will service it!
This clearly speaks about the Brand, and that the fame it got through its lifemaking, is so well earned, not only by the beauty of design, and precision in functioning, but for the excelence in finishing. It is often said that quality shows in the small details, and those details shown here, are really fantastic.
I should add, that the only Patek I own in my collection, is a reference 1589 from 1949, which incidentaly, has a similar movement caliber 12-120, which looks very similar to yours, and so it was a delicious experience for me to view and read this post, and learn a bit about its characteristics.
Thank you so much again, and I send you my cordial regards, wishing you´ll keep enjoying your Calatrava for many, many years, in good health.
Best cordial regards, Abel.