Jump to content
onzenuub

A Review of the New Omega Chrono Movement

Recommended Posts

onzenuub

We are going to review the new Omega chrono movement.

 

4143427123_e3f69795ce_o.jpg

 

4143427205_f1bb719007_o.jpg

 

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

 

4144187358_c8f2572e11_o.jpg

 

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

 

4143427361_c9f918eb31_o.jpg

 

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.

 

4143427399_cf0e4277c7_o.jpg

 

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

 

 

The movement is removed from the case:

 

4143427475_24e52b154f_o.jpg

 

Hands are removed:

 

4144187650_432bafa405_o.jpg

 

Dial is removed:

 

4144187718_de2c1ae6f5_o.jpg

 

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

 

4144187780_0f1f3fd7ae_o.jpg

 

This is the view after removing the first plate:

 

4143427759_c5bf2784ec_o.jpg

 

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:

 

4143427845_81ea055ed0_o.jpg

 

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.

 

4144187960_6b0e4c22c6_o.jpg

 

4144188048_8398769a59_o.jpg

 

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:

 

4143428067_f40ae6ecdd_o.jpg

 

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:

 

4144188202_25a5641770_o.jpg

 

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

 

The remaining gear of the minute transfer is removed:

 

4143428193_24f5966cd7_o.jpg

 

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.

 

4144188320_f4536c1a85_o.jpg

 

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:

 

4143428345_391e297c18_o.jpg

 

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:

 

4144188434_1a88610616_o.jpg

 

4143428481_33a5e1d57b_o.jpg

 

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

 

4144188598_37e91093b9_o.jpg

 

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.

Share this post


Link to post
Share on other sites
spboudart

Once a gain: A valuable post from Fransisco!

Share this post


Link to post
Share on other sites
scope

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

Share this post


Link to post
Share on other sites
tissotman

excellent review keep up the great work

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×