ETA 251.233 COSC Thermo Compensated Quartz Chronograph Watch Movement

ETA Caliber 251.233 COSC

ETA 251.233 COSC Thermo Compensated Quartz Chronograph Watch Movement

Manufacturer ETA
Caliber Number 251.233
Movement Type Quartz, chronograph
COSC?
Yes
Lignes 13.25”’
Diameter 30mm
Height
5mm
Battery Cell Number 394
Frequency 32,768 Hz
Stem Unknown (please comment below)
Hand Sizes Unknown (please comment below)
Jewels 27
Hacking Seconds?
Yes
Functions Central hours; central minutes; central chronograph seconds; central chronograph 60 minutes; 1/10 seconds; small seconds; 12 hours counter; date
Country of Manufacture Switzerland, Swiss made
Known Models
Invicta Jason Taylor Chronograph 12959, Christopher Ward C7 Racing Red (Add your watch to the comments below…)

The ETA caliber 251.233 is a thermocompensated quartz chronograph watch movement. This caliber is Swiss made with 27 jewels. Official documentation has been found dated February 18, 2008, so this movement has been available since at least that long. 251.233 was introduced as a direct replacement for the ETA caliber 251.232. This is a repairable quartz movement – if yours is having issues, it could be a bad coil.

Eta Cal 251233 Drawings

Unique Chronograph Functionality:

Rather than having a subdial for the 60 minutes totalizer, the 251233 has a central 60 minutes counter hand behind the central chronograph seconds hand. Other complications include a 1/10 second counter at 2:00, a 12 hour chrono counter at 10:00, a running small seconds indicator at 6:00, and a date calendar at 4:00.

Discontinued:

This movement appears to be discontinued. It is not found on the ETA website, nor can replacements be easily found online. Please comment below and share everything you know about this movement.

Caliber Commentary:

From Invicta:

“In this circumstance, the Thermo Compensated Movement is being utilized in these watches. The thermo compensated movement is made by ETA 251.233 and is comprised of 27 jewels. This fact differs from most quartz movements which generally do not have any jewels in the movement. The ETA 251.233 in entirely Swiss Made. These are the most accurate certified quartz caliber movements currently available; the movement maintains a -15 seconds per year. Due to their exceptional accuracy, thermo compensated quartz watches take accuracy in performance to another level in timekeeping.” (Source: http://www.invictawatch.com.hk/invicta/images/events/Store.pdf)

From Christopher Ward:

“To gain chronometer status, watchmakers submit their Swiss movements to COSC, an independent, non-profit making watch accuracy verification organisation based in Geneva, to be tested against the international standards of ISO and DIN.

Certification follows exhaustive testing. In achieving the coveted status of Certified Chronometer, a movement must not only be made from the highest quality components, but also be the object of special care on part of the finest horologists and technicians as it is painstakingly assembled.

Only movements which meet the precision criteria are granted an official certificate. Each uncased movement is individually tested for fifteen days, in five positions, at three different temperatures.

Movements are fitted with a second hand for tests and measurements are made daily with the aid of cameras. Based on all of these measurements, seven eliminatory criteria are calculated, each of which must be met.

The exacting and rigorous nature of the COSC certification process means that the achievement of Certified Chronometer status is extremely rare. In fact, of all the watches produced in Switzerland each year, just 3% bear the coveted COSC ‘bulletinde marche’ or certificate of watch performance.Which is why, when you read the words ’Certified Chronometer’ on a Swiss watch you can be sure that the movement behind the elegant dial is a rare example of fine Swiss watchmaking which is accurate, precise… and extremely rare.” (Source: https://www.christopherward.com/media/manuals/c7cosc_manual.pdf)

Battery Cell Strap Macro:

ETA 251.233 Battery

ETA 257.233 Tech Docs (PDF):

Additional Resources:

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Alojamiento web
Alojamiento web
7 years ago

For new collectors and those interested but unfamiliar with the vast number of movements available in the luxury watch market, the ETA movements prove to be a good place to start.

Jack
Jack
5 years ago

Although I only have 1 quartz watch in my collection it does have the ETA Caliber 251.233 COSC movement and I’ve had this for 3 years it only loses 3 seconds a year/

Brent
Brent
5 years ago

I own one watch that has the ETA 251.233 COSC movement. It runs about -4 seconds after six months. Overall I am pleased with this movement. The center chronograph minutes hand makes this movement stand out from other chronograph movements.

Jack Wright
Jack Wright
5 years ago
Reply to  Brent

Is it in an Invicta JT LE-12589.
That’s the watch I have with the same movement. 1 second a year on or off the wrist.

Jack Wright
Jack Wright
5 years ago
Reply to  calibercorner

Are there any parts of the ETA 251.233 that are prone to failure. Beside the battery. An answer would be most appreciated

Argya Trijono
Argya Trijono
3 years ago

I have Bulova use the same caliber.

Stever
Stever
2 years ago
Reply to  Argya Trijono

Which bulova do you have? I have a lunar module pilot Apollo 11 and cannot find the exact caliber it contains. It has three pushers. One at 2, one at 4 and one at 10. It’s a seven hander. What’s the pusher at ten o’clock do. Probably for the GMT but at this point not sure..

John Simmons
John Simmons
3 years ago

I Have an Eterna Kontiki with this movement.

Ahmet
Ahmet
2 years ago

Maranello using this movement and i liked.

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