Certina DS-2 Automatic Calibre 25.651 – Service

I have been meaning to feature a Certina DS-2 for a while on the blog. Having a penchant for vintage divers watches, the iconic “turtle back” originating from the late 1960s is certainly worthy of a feature, with its substantial look and novel design. It is powered by an in-house automatic Certina Calibre 25.651. One of the particularities of the DS-2 range is the floating movement design, where a rubber ring is sandwiched between the case and the movement, to absorb energy in case of a shock.

Certina DS-2 25.561


Here is a view of the famous “turtle back” caseback.


The removal of the caseback reveals the automatic Calibre 25.651, a rather nice looking movement. It also looks pretty clean so things are looking good.


The movement is removed from the case, note the rubber ring and the split stem type design.



The oscillating weight is removed.





And a closer view of the upper side of the 25.651.


Now moving on to the dial side.


The dial side now further disassembled.


I soon have the whole movement disassembled, ready for a detailed inspection and cleaning of the parts.Calibre 25.561 service



Re-assembly starts with a new mainspring.




I lubricate the balance jewels, and observe the balance, ensuring the endshake is correct. It is also the best time to check alignment of the hairspring as I have a near 360 degree view of it.


Centre wheel goes in first on this movement, this is a centre second.


The train is built up, and the trains and barrel bridges are fitted to the mainplate.


And I am nearly there with the upper side.





The date disc was very grubby.





Looking much nicer after a good clean.


I finish by fitting the automatic works. A very good looking movement indeed.Certina Calibre 25.561




I checked water resistance of the case, the test was successful.






I typically avoid polishing vintage watches to maintain originality, however this particular watch belonged to me and I was not happy with the finish you can see in the opening photo: the case had been incorrectly polished in the past resulting in very rounded edges. I re-lapped the case by hand, it is now much improved.Certina-DS-2-Service

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