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

 

Eterna-Calibre-1457U-Barrel-Bridge

 

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

 

 

Eterna-Calibre-1457U-Barrel-and-Mainspring

 

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.

Eterna-Lug

 

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

 

Eterna-Matic-Dial-and-Hands

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!

 

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2 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.

    Julian

    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.

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