Service: Omega Seamaster Chronograph 178.0515 calibre 3303A

As far as I remember, I haven’t blogged about the Omega calibre 3303 yet… which is a shame. This Seamaster has one inside, and it’s well worth having a look!

The dial design already lets us know that there is no 7750 inside, but something different.

The case will need a good clean as well…

Performance is pretty abysmal, as it’s been quite a while since the last service.

A first look. This doesn’t look like an Omega movement, and it doesn’t look like an ETA, either. And there is a good reason for that. The 3303 series was designed by F. Piguet, now called Manufacture Blancpain, owned by the Swatch Group. So strictly speaking an in-house (or rather in-group) movement.

The execution reminds me more of a Rolex movement than anything coming from ETA, and that’s a good sign. Piguet makes very nice movements indeed, and this is no exception.

Lovely decoration, lovely design.

The autowinder is unidirectional, and it could have been made bi-directional without a lot of sweat, but I don’t want to be too critical. It works well, and that’s what counts.

Somebody has inflicted some damage on the chronograph bridge.

With the chronograph bridge removed, you can see the vertical clutch of the chronograph second runner.

This photo shows the working of the vertical clutch. The two arms come in from the left and the right to separate the clutch.

The vertical clutch with the clutch arms removed. On the left, the heart-shaped cam of the hour recorder.

With the wheel bridge removed, we can see the full gear train.The movement also has a hacking lever to stop the movement when the crown is pulled out.

Now it’s time for the bottom plate. The movement has a quick-set date.

Date wheel and quick set wheel visible.

The keyless works.

All clean and ready for reassembly.

The balance jewels go in first.

As usual, I want the base movement to work before proceeding.

The only bugbear I have with this movement is the start/stop lever for the chronograph (right of the column wheel). It’s a bit puny, and would deserve an articulated lever and a spring.

Ready for the chronograph bridge.

The pallet fork is in place, and I can now put the balance in – the moment of truth!

The keyless works go in so that I can wind the movement.

And the balance is ticking. Let’s see how it’s doing…

Just put back together, the amplitude will improve. The movement is slightly slow.

Sorry for the bad photo quality, but this is after adjusting the two screws on the balance to set the beat rate.

The bottom plate is ready for its plate.

The rotor goes on…

Pretty thin for an automatic chronograph movement.

Dial and hands are back on.

And the movement is cased again.

Back in business!

I really like this movement. It’s got everything you want from a chrono (automatic, date, hacking lever, minute and hour recorder), it’s fairly small, and it doesn’t eat itself up like the Zenith El Primero, which would be the direct competition for this movement.

Beautifully constructed, a good performer, and a good looking movement. Now let’s put this in a smaller case, and I’ll buy one 😉

12 thoughts on “Service: Omega Seamaster Chronograph 178.0515 calibre 3303A

  1. Hi Christian!
    Is that rotor damage on the chrono bridge do you think?
    Excellent post as always 🙂
    Best regards, Ben

  2. Nice movement and great work as always.

    But I’m with you Christian – a slightly smaller case would be nice

  3. Thank you very much for the walkthrough, was a pleasure to read.
    Keep up with your postings.

    Lieben Gruß aus Köln

  4. Wonderful walkthrough as usual, thanks for sharing. The 3303 is an interesting movement I’ve not seen before and is nicely finished by the manufacturer too.

    Am I correct in thinking the hour recording mechanism is located on the same side as the rest of the chronograph works?

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