# Teardown: Zenith El Primero Defy calibre 400



## wilderbeest (Jan 9, 2012)

I took apart a Zenith El Primero Defy with the calibre 400 movement today. As usual, I have made a blog entry with lots of photos of the whole process, which should be quite interesting for Zenith afficionados!

Teardown + Service: Zenith El Primero Defy calibre 400 | Watch Guy

I would post some teaser photos, but the wus forum doesn't let me post my original photos due to size, and I'd rather clean watch parts than scale down images ;-)

Enjoy,

Christian


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## harris498 (Feb 10, 2011)

I really enjoyed reading that.


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## sempervivens (Sep 24, 2006)

wilderbeest said:


> I took apart a Zenith El Primero Defy with the calibre 400 movement today. As usual, I have made a blog entry with lots of photos of the whole process, which should be quite interesting for Zenith afficionados!
> 
> Teardown + Service: Zenith El Primero Defy calibre 400 | Watch Guy
> 
> ...


Very nice blog entry, thanks for that.

You wrote


> Apparently, the Zenith calibre 400 has 280 components, of which 225 are different.


 Sure about that ? Elsewhere I read "It does not include less than 354 parts including 227 different in the most complicated version" (but that may apply only to the triple date moonphase version).

You also wrote


> Here, we have a broken unlocking date spring... No problem, as it's really easy to get hold of Zenith parts. A big shout and thank you for an open policy which supports independent watchmakers!


That's the first time I hear that...I mean the part about "it's really easy to get hold of Zenith parts." I'd say : take advantage of it as long as it lasts. I'm afraid the general tendency nowadays is on the contrary not to sell parts any more to independent watchmakers. (I don't know why, it makes me wonder what they hope to gain with that closed policy.)


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## wilderbeest (Jan 9, 2012)

Cousins UK sells a wide range of Zenith movement parts - pretty much everything you might need. No case parts or bracelet parts, though.


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## sempervivens (Sep 24, 2006)

wilderbeest said:


> Cousins UK sells a wide range of Zenith movement parts - pretty much everything you might need. No case parts or bracelet parts, though.


thx for that, very interesting


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## CH-dmath (Mar 20, 2012)

Very interesting, thanks for sharing. I enjoyed the "wrapped around the backs of your eyeballs" bit. Not speaking from experience I hope...


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## Hartmut Richter (Feb 13, 2006)

Well, the 50h power reserve coupled with a 5Hz movement has to come from somewhere! No wonder the mainspring is extra powerful. I would be interested in how they service these at Zenith - going by your experience, a new mainspring must be a mandatory part of a standard service!

As for replacement parts, that's a no-go, I'm afraid. However, in the early eighties, Zenith were quite willing to get rid of old stock (Waldan International got loads of parts) so there is quite a bit floating around, at least for the standard calibres 400 and 410. If you want something special for the more modern calibres (practically everything else), you will be faced with a brick wall.

However, apparently all hope is not lost. The courts (can't remember whether Swiss or European) are dealing with cases trying to do away with this sort of "protectionism" and there seem to be good chances that the monopoly on parts will be overturned on grounds of unlawful elimination of competition or whatever they would call it. Who knows, if they make the practice illegal, Rolex might go out of business - they were the pioneers of this unwholesome habit.....;-)

Hartmut Richter


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## D N Ravenna (Apr 30, 2005)

Very nice Christian. That you so much for sharing!

Dan


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## John Chris (Jul 7, 2010)

That is so cool and so informative - thanks a million for sharing! Helps explain why I am not a watchmaker - my eyeballs would certainly have been truly scarred by now!

Incidentally, Rolex chose the cal. 400 movement to power its Daytona Cosmographs in 1986 because they were the best (and only reliable) automatic chronographs at the time, not because of the 10 beats-per-second frequency. In fact, for its Daytonas, Rolex 'dumbed-down' the movements to 8 bps for ease of service, and got rid of the date feature for brand design reasons (its watches had date windows only at 3 o'clock, and that wasn't doable on a chronograph). Rolex finally switched from the Zenith El Primero cal. 400 to its own in-house chronograph movement in 2000. And, as far as I know, the increase in frequency to 10 bps does enhance accuracy.

What I would love to know is what you use to lubricate the 'high-frequency' parts?

Thanks again,

Chris


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## mdatta (Apr 20, 2012)

From a guy who does not have the courage to take apart his Zenith the blog and photos were great! I felt like a kid looking over the watchmakers shoulder! Thanks!

Milt.


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## wilderbeest (Jan 9, 2012)

John Chris said:


> That is so cool and so informative - thanks a million for sharing! Helps explain why I am not a watchmaker - my eyeballs would certainly have been truly scarred by now!
> 
> Incidentally, Rolex chose the cal. 400 movement to power its Daytona Cosmographs in 1986 because they were the best (and only reliable) automatic chronographs at the time, not because of the 10 beats-per-second frequency. In fact, for its Daytonas, Rolex 'dumbed-down' the movements to 8 bps for ease of service, and got rid of the date feature for brand design reasons (its watches had date windows only at 3 o'clock, and that wasn't doable on a chronograph). Rolex finally switched from the Zenith El Primero cal. 400 to its own in-house chronograph movement in 2000. And, as far as I know, the increase in frequency to 10 bps does enhance accuracy.
> 
> ...


Hi Chris,

Thanks for the info about the Daytona. As far as I know, there isn't much gained in terms of accuracy by increasing to 10 bps. 8 bps tend to be the maximum for accuracy - otherwise, chronometers would work with 10 bps. But that is of course a disputable statement, and only my personal opinion.

I have put a photo of the watch sitting on the oiling chart http://watchguy.co.uk/wp-content/uploads/2012/05/IMG_1437.jpg on the blog post, and the balance jewels are on there as well. They get Moebius 9010 - if you click on the photo, you get a high-res image of it, and you can see the oil types used on the movement. You need 5 different lubricants for this movement, and you have to re-mortgage your house to buy them ;-) The 9010 costs £10,000 per litre (you only buy 2ml for £20 at a time), and the other lubricants are just as expensive. The Moebius 9415 only has a single use - on the pallet jewels.

I do stick to oiling charts meticulously, as it helps increase the service interval and to maintain a constant performance.

Best regards,

Christian


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## wilderbeest (Jan 9, 2012)

Hartmut Richter said:


> Well, the 50h power reserve coupled with a 5Hz movement has to come from somewhere! No wonder the mainspring is extra powerful. I would be interested in how they service these at Zenith - going by your experience, a new mainspring must be a mandatory part of a standard service!
> 
> As for replacement parts, that's a no-go, I'm afraid. However, in the early eighties, Zenith were quite willing to get rid of old stock (Waldan International got loads of parts) so there is quite a bit floating around, at least for the standard calibres 400 and 410. If you want something special for the more modern calibres (practically everything else), you will be faced with a brick wall.
> 
> ...


Ah - that explains the ready availability of parts for the calibre 400! I will correct my blog entry to that regard. Yes, the new mainspring is available as well - for a few pounds shy of £100, and part of a standard service.

It would be great to see a free market for watch parts. In the end, it should be the customer's choice where he wants his watch serviced.

Best regards,

Christian


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## keegemit (Apr 1, 2012)

Thanks for posting!


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## Hartmut Richter (Feb 13, 2006)

As far as I know - and I am no watchmaker! - they use a "dry" lubricant based on Molybdenum bisulphide for the escapement. This means that the escapement must be coated with the stuff (i.e. it never comes off) or that the stuff is highly adhesive to the metal (far greater adhesive than cohesive properties). 5Hz will give a fair increase in accuracy over 4Hz but the problem is the lubricant. Once that is solved, you can notch up the beat rate. One other negative aspect of a higher beat rate, however, is the power required and the power reserve it gives you. Which is one major reason is it rarely used (your standard 40h ETA 2824 would go down instantly to 32h if you notched it up to 5Hz). The El Primero still has so much power reserve because it was designed with such a high beat rate in mind - _post hoc_ compensation rarely works well.

So how did you clean and lubricate the mainspring during your service? Or did you just leave it entirely as it was?!

Hartmut Richter


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## RogerP (Mar 7, 2007)

Absolutely fascinating - I love stuff like this. I hope we will see more like it in the future.

Roger


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## D N Ravenna (Apr 30, 2005)

RogerP said:


> Absolutely fascinating - I love stuff like this. I hope we will see more like it in the future.
> 
> Roger


No disagreement from me! Wonderful to see things like this on a site!

Dan


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## John Chris (Jul 7, 2010)

D


wilderbeest said:


> Hi Chris,
> 
> Thanks for the info about the Daytona. As far as I know, there isn't much gained in terms of accuracy by increasing to 10 bps. 8 bps tend to be the maximum for accuracy - otherwise, chronometers would work with 10 bps. But that is of course a disputable statement, and only my personal opinion.
> 
> ...


Holy Petroleum, Christian, that's some chart! I am amazed! Thanks so much for your posts.

Chris


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## wilderbeest (Jan 9, 2012)

Hartmut Richter said:


> As far as I know - and I am no watchmaker! - they use a "dry" lubricant based on Molybdenum bisulphide for the escapement. This means that the escapement must be coated with the stuff (i.e. it never comes off) or that the stuff is highly adhesive to the metal (far greater adhesive than cohesive properties). 5Hz will give a fair increase in accuracy over 4Hz but the problem is the lubricant. Once that is solved, you can notch up the beat rate. One other negative aspect of a higher beat rate, however, is the power required and the power reserve it gives you. Which is one major reason is it rarely used (your standard 40h ETA 2824 would go down instantly to 32h if you notched it up to 5Hz). The El Primero still has so much power reserve because it was designed with such a high beat rate in mind - _post hoc_ compensation rarely works well.
> 
> So how did you clean and lubricate the mainspring during your service? Or did you just leave it entirely as it was?!
> 
> Hartmut Richter


Hi Hartmut,

Interesting - where did you get the information about the dry lubricant from? I am following the Zenith oil chart for the 400 movement (which you can see here: http://watchguy.co.uk/wp-content/uploads/2012/05/IMG_1437.jpg), and it clearly shows Meobius 9010 on the balance jewels and Moebius 9415 for the escapement - which is pretty much standard for any watch movement.

I'm afraid I also have problems to follow the 5Hz is more accurate than 4Hz argument. If that was the case, wouldn't other manufacturers have adopted 5Hz movements? The route to more accuracy seems to go another way, e.g. Omega's co-axial escapement. Think of a Bulova Accutron at 360Hz - very accurate, but still only to about a second a day! So the reasoning more frequency = more accuracy doesn't quite hold for me. Nevertheless, I very much admire any watch manufacturer who managed to make such a great movement!

For the mainspring, it is most advisable to change the barrel at a cost of roughly £100. In the end, it is the client's decision if they want to spend the money, but I advise them to do so.

Best regards,

Christian


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## sempervivens (Sep 24, 2006)

On the internet I found a few claims that Zenith caliber 410 has 354 parts (including 227 different) and Zenith calibre 400 would have 280 components (of which 225 are different). 

Is it all only sales talk?

I find already strange that caliber 410 is supposed to have 74 more components than cal. 400, but only two more 'different ones' ?!?

Just goes to show how little we know. 

We are all Zenith Primero fans here, but who knows the truth about the number of components?

Maybe you can do us all a favour and count the number of components when you put the watch back together again.

If I look at the parts list, I count only 135 parts. What am I missing here?


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## wilderbeest (Jan 9, 2012)

sempervivens said:


> On the internet I found a few claims that Zenith caliber 410 has 354 parts (including 227 different) and Zenith calibre 400 would have 280 components (of which 225 are different).
> 
> Is it all only sales talk?
> 
> ...


I thought long and hard about that, too! And I think I have found the solution.

Take for example the rotor - one part in my box. But it has a ball bearing (each ball a part), inner and outer ring for the bearing, etc.

Or the balance assembly - one part in my box. Balance cock, regulator, beat error regulator, hairspring, collet, balance, balance staff, jewel setting, shock spring for jewel setting, etc....

So you can probably get to 280 components like that.

BTW - reassembly has to wait a bit - Cousins UK delivered the wrong parts :-(


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## sempervivens (Sep 24, 2006)

(for some unknown reason my previous post was duplicated here, so I removed it)

thanks for the reply Wilderbeest


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## Hartmut Richter (Feb 13, 2006)

My information on the dry lubricant is from "Klassische Armbanduhren" (Peter Braun, ed.; publ: Heel Verlag, the ones who publish the German watch magazine "ArmbandUhren"). I have also seen it in other places, mainly on the www. The problem with lubricants in general on that escapement is that the centrifugal forces get rid of them so quickly. So either you use stuff that really sticks or you are servicing more frequently or running dry in the latter half of the period between services. At least that's what they preach! I think it must have a fair share of truth to it, otherwise more makers would use 5Hz movements (without silicon) - especially in view of the fact that quite a few experimented with them but abandoned them!

Hartmut Richter


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## wilderbeest (Jan 9, 2012)

Interesting stuff! I'd like to get hold of some dry lubricant for testing! 

The Moebius 9415 is very sticky, and works well on 8bps movements. So I guess with only 20% more speed on the escapement wheel, all should be fine. 

Centrifugal force should just bring it to the right place, and the pallet jewels will make sure it stays there. From my photos, I count 20 teeth on the escapement wheel, so 20 back and forth swings of the balance per turn = 4 seconds per turn. Considering the diameter of the escapement wheel, these aren't mad centrifugal forces. I think a baby louse wouldn't get too excited about it as a fairground ride ;-)

The index wheel of a Bulova Accutron turns a 1 1/4 turn per second! But that doesn't need lubricating ...


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## Hartmut Richter (Feb 13, 2006)

wilderbeest said:


> From my photos, I count 20 teeth on the escapement wheel, so 20 back and forth swings of the balance per turn = 4 seconds per turn.


Ehrm, not quite! Each *half* beat releases one tooth so 20 teeth will be passed round once in 2 seconds, not 4. As for whether and to what extent this would increase the rate of loss, _je ne sais_.....

Hartmut Richter


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## wilderbeest (Jan 9, 2012)

Hartmut Richter said:


> Ehrm, not quite! Each *half* beat releases one tooth so 20 teeth will be passed round once in 2 seconds, not 4. As for whether and to what extent this would increase the rate of loss, _je ne sais_.....
> 
> Hartmut Richter


Ouch - that's what you get from posting in the middle of the night when your baby daughter has woken you up ;-)


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## wilderbeest (Jan 9, 2012)

Got the wrong date spring from Cousins - they said they will sort it out with their supplier. This might yet take a while ;-)


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## wilderbeest (Jan 9, 2012)

A little update - most of the movement is back together, but I'm still waiting for the new unlocking date spring, so I couldn't put it completely together. Looking good, though!

Movement Reassembly: Zenith El Primero Defy calibre 400 | Watch Guy

Enjoy,

Christian


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## Hartmut Richter (Feb 13, 2006)

Great stuff! Did you test for positional errors with the timing machine at this stage? If so, what are the results may I ask?

Hartmut Richter


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## wilderbeest (Jan 9, 2012)

Hartmut Richter said:


> Great stuff! Did you test for positional errors with the timing machine at this stage? If so, what are the results may I ask?
> 
> Hartmut Richter


I'll run that tomorrow and post it. I normally do that further down the line, but it doesn't really matter and now I am intrigued myself ;-)


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## Surfstang2020 (May 3, 2012)

Very nice 


Sent from your moms phone


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## John Chris (Jul 7, 2010)

Thanks again, Christian, for sharing your labour of love with us!


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## wilderbeest (Jan 9, 2012)

Hartmut Richter said:


> Ehrm, not quite! Each *half* beat releases one tooth so 20 teeth will be passed round once in 2 seconds, not 4. As for whether and to what extent this would increase the rate of loss, _je ne sais_.....
> 
> Hartmut Richter


I am too easily intimidated by the voice of authority ;-)

The Swiss lever escapement releases one tooth every full swing (balance wheel once back and once forth, or pallet fork one way and pallet fork the other way), so in a 10 bps movement, 5 teeth are released every second. 20 teeth on the escapement wheel take thus 40 periods = 4 seconds. That's why the formula to calculate the beat rate of a movement in bph is [sum of driving wheel tooth count] * 2 / [sum of driven pinion leaf count]. The "2" compensates for the fact that it takes 2 swings (one back, one forth) to release a single tooth of the escapement wheel. The driving wheel count includes the teeth of the escapement wheel, as it drives the pallet fork / balance.

Again, it's 2 o'clock at night and I'm up because my little baby daughter woke us up, but I *think* I'm right.

There is a great web site with moving illustrations of escapements, and the Swiss lever is here: Swiss Lever Watch Escapement in Motion. You can see how a tooth is released with every full back and forth movement of the pallet fork.

Back to bed ;-)


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## wilderbeest (Jan 9, 2012)

Surfstang2020 said:


> Sent from your moms phone


Best tagline I've ever seen and probably will ever see!


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## phoobo (Mar 21, 2012)

AFAIK the molybdenum disulphide only survives as a recommendation for the escapement lubrication because that's what existed when the EP first came out. A great many experienced and reliable watchmakers use 9415 (invented only in the new millennium) in place of that today. Not sure what they do at the service centers. The real test, I suppose, is to check for spray remnants on the surrounding surfaces after a few weeks of use.


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## wilderbeest (Jan 9, 2012)

phoobo said:


> AFAIK the molybdenum disulphide only survives as a recommendation for the escapement lubrication because that's what existed when the EP first came out. A great many experienced and reliable watchmakers use 9415 in place of that today. Not sure what they do at the service centers. The real test, I suppose, is to check for spray remnants on the surrounding surfaces after a few weeks of use.


The oiling chart actually says that the escapement wheel has "prelubrification", and also states that 9415 is used afterwards. So it is treated with something at the factory, but 9415 is used during servicing.

I guess the process of applying the MoS2 at the factory can't be replicated during a service. In my humble opinion, 9415 is perfectly good for the job. 8pbs movements with escapement wheels with less teeth have exactly the same turning speed, and they make it from service interval to service interval. As the watch hadn't been serviced for 21 years, even the MoS2 had worn off as the timgrapher image shows a pretty bad performance.

I'm letting the movement run at the moment, and I'll check the escapement / pallet jewel lubrification in a couple of days.


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## wilderbeest (Jan 9, 2012)

Hartmut Richter said:


> Great stuff! Did you test for positional errors with the timing machine at this stage? If so, what are the results may I ask?
> 
> Hartmut Richter


Hi Hartmut,

I've tested the positional variations and I'm pretty impressed!

POSITIONBEAT RATEAMPLITUDEBEAT ERRORDD0s3000.2DU-3s3000.2CR0s2910.2CD+7s2860.5CL+1s2930.4CU-4s2750.3


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## sempervivens (Sep 24, 2006)

That's interesting. Could you explain what the 'DD', 'DU', 'CR' etc stand for ?


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## wilderbeest (Jan 9, 2012)

sempervivens said:


> That's interesting. Could you explain what the 'DD', 'DU', 'CR' etc stand for ?


DU = Dial Up, DD = Dial Down, CL = Crown left, CR = Crown Right, CU = Crown up, CD = Crown Down

Sorry, should have put that in.

Best regards,

Christian


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## sempervivens (Sep 24, 2006)

Thanks !

Dial down or crown right may be the best positions then. Will try it out b-)

BTW : thanks to your advice about Cousins I ordered a part from them (not a Zenith part but Omega, which is also becoming increasingly difficult to get). Got it this morning. 

Thanks again Christian !


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## RogerP (Mar 7, 2007)

Wow - amazing how much better everything looks all cleaned up and (partially) re-assembled.

Roger


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## Hartmut Richter (Feb 13, 2006)

Well, 11 seconds between lowest and highest is usually too high for a new El Primero. Although we are admittedly dealing with a slightly worn, vintage movement. What seems odd is that the difference is not between lying and hanging positions but inside the four hanging positions.....

Hartmut Richter


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## wilderbeest (Jan 9, 2012)

Hartmut Richter said:


> Well, 11 seconds between lowest and highest is usually too high for a new El Primero. Although we are admittedly dealing with a slightly worn, vintage movement. What seems odd is that the difference is not between lying and hanging positions but inside the four hanging positions.....
> 
> Hartmut Richter


It's a 21 year old movement - I find this a very decent performance indeed, but I am not a Zenith expert, of course.

What's your take on the speed of the escapement wheel? Have I got it wrong again???

Best regards,

Christian


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## Hartmut Richter (Feb 13, 2006)

Thanks for the link. On reflection, you are quite right - the ultimate speed is once round every 4 seconds, not 2. The fact is that one half beat releases one tooth (not one full beat) but that different teeth are involved. The critical point is that one half beat only allows the entire wheel to travel *one half* of the distance between successive teeth. Therefore, 4 seconds for the EP escapement wheel it is.

Hartmut RIchter


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## daveenty (Dec 17, 2011)

First time I've visited this thread.
Thought it was about time really as I'm the owner of the watch which has been dissected.

Let's face it people, it's passed it's first flush of youth, and possibly not going to win any beauty contests. But it's mine, and I feel like I need to stand it's corner.

First and foremost, an immense thanks to Christian for taking it on in the first place. I wasn't really bothered about having any work done to it until I saw his work and his amazing attention to detail on another (Omega) forum.

This little thing has been sat in a box in the corner feeling sorry for itself for quite some time, and I realised that a bit of care and attention wouldn't go amiss. This was when I asked Christian if he would have a look at it. I knew that it would get what it needed, and was told upfront an approximate cost for the work which was going to be done.
I've been kept informed via email with photos and explanations of exactly what's been happening from strip down to (partial) rebuild and am more than happy.

The watch was/is (not sure at the moment) for sale, though I wanted it right before selling it, as I'm a great believer in "do unto others".

Once it comes back to me then I'll wear it once or twice, then contact my original buyer (who's aware of this thread and all the watch history) or re-advertise it.

My one consolation now is that I have so many pictures of this service that if I do ever sell it I can prove exactly what it is.

I do need the money in to cover other bits and pieces (like food and heating), but it may be a while before I decode to move it to a better home.

Thanks again Christian, excellent job.


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## wilderbeest (Jan 9, 2012)

Well, the mystery of the unlocking date spring is solved! I raised the issue with cousins on the 30th of May, and they now have come back to me.... The spring they delivered is a replacement for the original. Even though it looks completely different, it's the right spring. Doh!

Makes me think that it wasn't the first time this happened, and that they changed the design of the spring quite dramatically to prevent this happening in the future. Mental note - replace this on any Zenith calibre 400 you open!









Also, I checked around the escape wheel, and no oil has come off, and there is still a nice film between pallet jewels and escape wheel when they engage. As you would expect, really, as Moebius 9415 is excellent stuff!

I have now put the movement together completely, and expect a new crystal and gaskets in the mail tomorrow, so I will be able to put the watch together next week.

Christian


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## wilderbeest (Jan 9, 2012)

Now I have all the parts I need, and I've put together the Zenith again:

Final Reassembly: Zenith El Primero Defy calibre 400 | Watch Guy

That's the end of the story - 2 days on the bench in "quarantine", and then it's back to Dave!

Enjoy,

Christian


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## RogerP (Mar 7, 2007)

Well done!


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## sempervivens (Sep 24, 2006)

very nice, thanks for sharing and glad to hear that Cousins got it right


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## LouS (Oct 6, 2009)

Christian, terrific links and the thread ain't bad on its own merits either. Many thanks for posting this.


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## mdatta (Apr 20, 2012)

Christian, thanks for the tour through the calibre 400. I learned a lot, and I understand and appreciate the expertise you bring to your work. Appreciate it! Milt.


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