: My question has more to do with the Chronomatic movement itself. We
: all know that it was comprised by a Buren microrrotor automatic
: movement and a Dubois Depraz developed chrono module, and that
: it was launched in 1969. Buren, however, went out of business
: around 1973-74, whereas Chronomatic equiped Heuers were
: available until probably the early to mid eighties.

I believe that, at the time Buren went out of business, there were abundant supplies of the Buren base modules (that were used for the Caliber 12 series of chronographs). I believe that between what was on hand at Buren, and what was on hand at Heuer, there were plenty of the modules to continue production for some years . . . well into the 1980's.

: Also, Calibre 7740 from ETA is clearly the same DD chrono module on
: an ETA manual wind movement. 7740 is the caliber inside some of
: the black PVD Monacos recently reviewed in this forum.

I have some notes on this question, which I will need to review to provide a more detailed answer. I believe that Valjoux used many of the same components (from Dubois-Depraz), and so the 7740 was almost a derivative or continuation of the Caliber 12 (only assembled by Valjoux rather than by the Caliber 12 joint venturers). All this is complicated by my having some uncertainty as to exactly "who" did "what", in terms of producing parts, assembling movements, making adjustments, etc.

: Does anyone has an idea of what is the story?

I will try to check my notes. I have lots of information, and notes from conversations with some of the true experts, but it is difficult to find the time to write up / memorialize all the information.

Jeff