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onzenuub

A Review of the New Omega Chrono Movement

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onzenuub

We are going to review the new Omega chrono movement.

 

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After removing the case back we check that an Asian 7750 has been employed for this modification.

 

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The first visible problem with this modification is that the chrono pushers are not placed in the correct position. Here the difference is shown:

 

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As previous picture shows, the pushers are one minute up and down in the rep. This happens because the movement that Omega employs is not based on the 7750, and the pushers are in a different place. Therefore, all Omega reps will have this flaw, all.

 

¿Can this problem be solved? Yes, it is possible. The movement has a retaining ring (see previous pictures). In this ring it is possible to install levers, like in the Grahams. For example, next picture shows the ring and lever employed in the Graham to shift the movement from the pusher on 3 position to internal 2 position.

 

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Will the factories employ a similar solution? …who knows…

 

 

The movement is removed from the case:

 

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Hands are removed:

 

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Dial is removed:

 

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And the first plate is visible. Red circles show the 5 screws to be removed to unassembled this plate.

 

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This is the view after removing the first plate:

 

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This last picture shows part of the modification. On positions 6 and 9 a two floors gears are employed to take the motion from the movement and lifting it up. A picture of one of these two floors gears (they are equal) follows:

 

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Follow the pictures of the two faces of the first plate. As shown, all the pins of the gears have a jewel in the plate. This is very good.

 

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In addition, we can compare this mod with the mod of Potuguese, Daytona and AP with seconds at 12. These reviews are here:

 

Portuguese: http://www.replica-watch-guide.net/forum/i...?showtopic=3156

 

Daytona: http://repgeek.com/showthread.php?t=47094

 

AP: http://repgeek.com/showthread.php?t=26985

 

After this comparison, this new modification seems (now and after finishing the review) much better than AP seconds at 12, and very, very much better than Portuguese and Daytona. There are no gears rotating over the plate and no buttons to hold the gears.

 

Two gears are employed to shift the minute counter form 12 to 3 position. There is no two floors gear in this case, because the natural output gear is now in a very high position.

 

The three new output gears are now removed:

 

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As seen, there are no jewels in the bottom of the outputs, there are in the top. A pitty. We only need to consider the seconds output that it is always running. Minute and hour counter are normally stopped. As we are going to check, with only one jewel more in the seconds output the mod will be practically perfect.

 

Instead of employing a jewel, the rotating surface of the gears against the plate has been reduced, as show by next picture:

 

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It is a reasonable solution, although, of course, a jewel would be better.

 

The remaining gear of the minute transfer is removed:

 

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Then it is possible to see a jewel there. We should remember that in the top there is always a jewel for each gear.

 

Next step is to remove the second plate, after removing 3 screws.

 

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Now the A7750 movement is visible with the two floors gears. As we commented before, the minute counter does not use a two floors gear, because the output is higher, as next picture shows with a red circle:

 

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Previous picture also shows with a yellow circle that there are jewels for the two floors gears. Therefore, all the gears have jewels up and down, except the final gears that use a reduced surface of contact down.

 

Follow pictures of the two faces of the second plate:

 

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One of the problems of the modified movements is the sunken datewheel. In this movement is clearly noticeable, as next picture shows.

 

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In addition, the photo shows a shine that comes from the first plate. This shines may be reduced painting of black the area close to the DW window.

 

 

SUMMARY

 

GOOD

 

* Modification quite well designed.

 

* Only needs one jewel to be a practically perfect mod.

 

* Very, very much better than Daytona and Portuguese, and quite better that AP with seconds at 12.

 

* I guess that it is going to be reliable.

 

 

BAD

 

* It is a movement that it is very hard to assemble, problematic, it tends to stop if everything is not perfectly assembled. I think that the origin of the problem is the very short pins of the two floors gears. However, if it works well at the beginning it should be reliable.

 

* Sunken DW.

 

* Incorrect position of the pushers.

 

Thanks for reading,

 

Francisco.

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spboudart

Once a gain: A valuable post from Fransisco!

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scope

Thanks for the review. I'm really thinking about getting one of these.

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tissotman

excellent review keep up the great work

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