KELEK TENOR DORLY 1376 JUMP HOUR AUTOMATIC CHRONOGRAPH 1975
This is likely the first in the World jump hour chronograph by Kelek SA aka Société Jean-Raoul-Gorgerat Kelek SA (or JRGK SA in short). Kelek didn't really develop watches but used ebauches movements and had them modified. This chronograph which was the smallest in its day is very collectible and very hard to find with most found with Waltham branding. It is based on a plain but robust TD1393 calibre by Tenor-Dorly known for cool and quality jump hours from the 1970's. The build is modular with the chronograph section subcontracted to Dubois-Depraz which also created the chrono module for the most famous Heuer/Breitling 'Chronomatic'.
If you compare the standard TD1393 calibre with this TD1376 you might not even notice the difference at first sight to indicate that this is a stop watch. The front side however shows a seconds pinion in the very center and a minute-totalizer pinion at 11. The back side has had the automatic winding gears and oscillating weight raised from the base movement and the chronograph section fitted somewhat in between. It works and is reliable although it is just not breathtaking like some other vintage chronographs. I wonder how a bullet-proof A.Schild jump hour calibre would look like with a chrono function added :) As I could not find any manuals for this calibre it took me a while to approach it from the inside. Finally I made this step so please enjoy a few pictures of the gutted movement.
The chrono module of basic construction consists of two layers sandwiched in between three plates. Disassembly is not difficult and must be sequenced properly with focus on releasing the springs. The technical terms applied might not be fully correct but the hammers, clutch levers and heart-shaped reset wheels can be easily observed and analyzed. I hope these shots will be very useful for the future to check proper alignment of all the vital parts. The issue I had was that the minute-recorder was advancing despite not being activated. I thought that it's a problem with an intermediate pinion-gear that is driven by the mainspring-barrel. But in the end after a full strip the solution was super simple and required adjustment of a spring that locks the minute-recording brake - shown in the left picture next to the balance jewel.
Keywords: kelek, jrgk, waltham, tenor dorly, td 1376
Market value: 750-1500$ (brand, bracelet, condition, box)