Eterna Matic 3000 Sevenday Calibre 1457U – Service

This week I am featuring this Eterna Matic 3000 Sevenday on the blog. The watch is powered by Eterna’s Calibre 1457U, an automatic movement with a day date complication and quick set date mechanism. Eterna had a pioneering role in the development of self winding calibres, with the development in the late 1940s of the first Eterna Matic movement, using a friction-reducing ball-bearing mounted rotor system. The 145X and 146X movement family follow on from the success of the first Eterna Matic, and were known as ultra-thin automatic movements ( 3.6 mm thick, and 4.15 mm for the day date).  It is commonly known as the ancestor of the famous ETA 2892 movement, the high end Calibre by ETA found in many prestigious watches for the last few decades. It is worth noting that ETA was founded by Eterna, so it is no surprise that even the movements produced nowadays by ETA (currently owned by the Swatch Group) share some  common DNA with Eterna calibres.

Eterna Matic 3000 Sevenday Service


I open the case, and straight away the similarity with the ETA 2892 is obvious, starting with the bearing of the oscillating weight.  Eterna Calibre 1457U


This was my first time working on this particular movement, but having worked on several ETA 2892s in the past I felt right at home. Here the automatic works is now separated from the movement.Calibre 1457U Service


Calibre 1457U regulator

A close up of the interesting micro adjustment device on the regulator. This particular movement has the “Eterna-U” shock protection system (hence the letter “U” after the movement number).



The movement is running, but the hands do not move, minute and hour hands are both loose on their respective posts.Eterna-Matic-Dial


Calibre 1457U Dial Up


I start stripping down the dial side





With the day disc out of the way we uncover more of the dial side of the movement.Calibre 1457U dial-up before service


The dial side is nearly fully disassembled here. Note that there is an end stone on the lower side of the pallet.Calibre 1457U dial-up before clean


I then move on to the upper side of the movement. I am loving the gold characters on the main plate, it looks beautiful.Eterna-Matic Calibre 1457U




The winding mechanism under the barrel bridge is very similar to the ETA 2892, although the spring/ locking mechanism is slightly different.



Eterna Calibre 1457U Balance



The balance has a blue hairspring, very nice.




I strip the barrel and mainsring, it will definitely benefit from a good clean. Breaking grease has escaped from the surface of the barrel wall and dried up.Eterna-Calibre-1457U-Mainspring


The watch and movement are now fully disassembled, and the parts are ready for cleaning.Eterna-Calibre-1457U-disassembled





After ultrasonic clean of the parts I start re-assembly by fitting a new mainspring in the barrel.




The barrel bridge, train wheels and bridge are now in place.Calibre 1457U re-assembled


The dial side is re-assembled.Calibre 1457U re-assembled dial up


The movement responded very well to the service, it is ticking again nicely with excellent amplitude.



I now turn my attention to the case. There were a few service marks left by previous watchmakers inside the case back, however it is unusual to see them on the case lug!



The case is ultrasonically cleaned, and the crystal replaced. Eterna Crystal Replacement



The hands are back in place. As they were loose when I received the watch I was pleased to find that the fit was excellent. No work or replacement required here which is good news.



And I finish by fitting a new gasket.Eterna-Matic-Gasket-Replacement


The watch looks superb, and importantly it can now fulfil its intended function as the hands are now doing their job!


6 Replies to “Eterna Matic 3000 Sevenday Calibre 1457U – Service”

  1. Fantastic work as always.

    How do you find replacement mainspring for these vintage movements? How often do you have to keep the original spring in place?

    Same quick question for the crystal. Where to you obtain the replacement ones?

    Thank you.


    1. Hi Julian, in this case I used a generic mainspring, made by a company Generale Ressorts. I have a catalogue listing their mainsprings available for different manufacturers/ calibres.
      If there is no equivalent listed I measure the spring, thickness, height, length, barrel diameter to find a suitable alternative.
      I tend to change the mainspring as a matter of course as part of the service, provided I can find a suitable replacement.

      I used a generic tension ring type replacement acrylic crystal in this case, the trick here is to get the size exactly right, a vernier gauge helps.

  2. How do you set the day and date on this watch
    Eterna-matic 3000 with window for day and window for date

    1. Hi
      There is a quickset function for the date on this movement, it works by pulling the crown. The day is set by setting the time and running through 24hrs as many times as needed.
      I hope this helps!

  3. What a beautiful movement.
    I have this watch but with Cal. 1501K.
    Serial # 5827803.
    When would that model have been introduced?
    Du you change the mainspring when there is already an “unbreakable” mainspring in the barrel

    1. Hi Helmut
      I don’t know for sure when the model was introduced.
      Ref the mainspring, I always replace it as part of a service when it is possible and a replacement is available.
      Best regards

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