DD2000 (Dubois-Depraz) chronograph module rebuild
Something slightly different as this shows the rebuild of a DD module as used by everyone from Tag to Audemars Piguet. Omega use these in the Speedmaster reduced model as well and in all cases, you can tell there is a module as the chronograph pushers are offset from the crown, being closer to the dial of the watch.
They are not intended to be serviceable and usually are returned to factory for an exchange if they are causing excessive amplitude drop in the base calibre. There is, however, no issue with servicing these as long as parts are not required because, they are just not available to buy.
This is from a Baume and Mercier watch and the module sits on top of a BM13283 which is essentially an ETA 2892. First step is to rebuild the 2892 and these are nice calibres to work on so, no particular details of that. Here is the base movement finished and what’s noticeable is that there is nowhere to mount the hands as there is just a gear at the centre of the movement to drive the DD module. This is the back plate of the DD, viewed from the dial side and the module gets built on here.
The wheel that brings the drive from the ETA is added close to the centre and the lower wheel is there to drive the hour and minute hands
Part of the the chrono train and central seconds heart are added.
Hammers and chrono bridge fitted.
Minute counter wheel (on left at 9 O’Clock) and hour counter wheel (at 6 O’clock) added plus some of the start/stop/reset mechanism.
Fitted the clutch wheel just above the centre and this works when the upper T bar spring presses down onto it. When that happens it drives the centre part of the chrono and all the rest from that. Added some more parts of the mechanism at the upper which is the start/stop.
Added more parts of the stop/start mechanism and at the bottom, the lock which works to stop the whole chronograph part moving when not in use.
Added the reset lever and the hammer operating lever. The reset lever had some corrosion and that was removed but, some staining can still be seen at the lower right.
Remaining parts added and the module is complete.
Front plate fitted and it’s ready to be refitted to the base movement when the date magnifier glass is added.
This is the rear of the module showing how it receives the drive from the 2892.
The module and 2892 are joined and this is the rear (top) of the 2892 while running.
From the front, the date magnifier can be seen and it’s ready for the dial and hands.