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  1. Sgt_Bilko Apr 7, 2016

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    I have a 1997 Cal 861 De Ville and wouldn't mind taking a look inside to see the movement but it's not clear how the back comes off and I wondered if anybody here knows the answer? Is it one I can safely unscrew with a rubber ball or does it have to be prised open somehow?

    I've occasionally seen these online with the back off but never known how it was done. It was with a watchmaker a year or so ago and he didn't mention anything being wrong but I'd like to photograph it.

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  2. Spacefruit Prolific Speedmaster Hoarder Apr 7, 2016

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    It's a snap back. Unless you are REALLY proficient at removing snaps then I wouldn't do it. It's so easy to mark the case. I have no doubt you will see some marks already.
    I believe this reference has an 18kt gold bezel
     
  3. dx009 Apr 7, 2016

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  4. Sgt_Bilko Apr 7, 2016

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    I have a rubber ball for watches. It's hard to see a place where the back can be popped open on this one. Would it do any damage if I twist it with the ball to look for the point where it can be popped open? I have a tool where the watch can be placed securely before lifting the back off.
     
  5. Sgt_Bilko Apr 7, 2016

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    I'm not 100% sure if this one has a white gold bezel or stainless steel. It's very slim but I think it's all stainless steel.
     
  6. dx009 Apr 7, 2016

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    I'm an idiot. I don't know why I added the rubber ball since it's a snap back. You can use it to rotate it around a little bit until you find a spot where a watch knife tip should be inserted but the thing is, many watches don't have that little space between the case back and the case...

    Theoretically a screw driver could do it but you need to be gentle and accurate. :) And don't let it slip.
     
  7. Sgt_Bilko Apr 7, 2016

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    I have the proper tools for prising open case backs and there is a little trick about placing sellotape over the spot to minimise the risk of scratches but in this case the space itself is not clearly identifiable. It's an awkward so and so!
     
  8. dx009 Apr 7, 2016

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    Really old watches didn't always have that space, but newer ones should... You can try with a thin piece of hard plastic or wood. It would reduce potential damage...
    Maybe this will help. Also, try to rotate it a little bit both sides before trying to open. Just in case it might be a little stuck.
    [​IMG]
     
  9. Archer Omega Qualified Watchmaker Apr 7, 2016

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    Please note that the gaskets on these are typically a hard plastic gasket that is designed to deform in order to provide a seal. This means the gasket is really a single use item, and will not seal as well once it's been used once. I would suggest taking this to someone who has the knowledge to open it without damage, can get a new gasket, and has a proper press to close it again.

    If you need the gasket parts number (or even want to confirm the bezel material) send me a PM with the serial number and model,. and I'll look it up for you.

    Cheers, Al
     
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  10. Sgt_Bilko Apr 7, 2016

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    This is a strange one because I look at all the other watches here and it's not hard to see how they open but this one is a bit particular.
     
  11. Sgt_Bilko Apr 7, 2016

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    Thanks Al. I do have a press to close it but I don't want to damage anything and it sounds like a job that is better left to a professional. It's just a pity there is nobody within close driving distance.

    Something I'm a little curious about is why the winding action feels quite different to another Cal 861 here on a Speedy from 1971. Somehow I just prefer the feel of the way the Speedy winds.
     
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  12. abrod520 Apr 7, 2016

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    Could be that it needs a service / replacement mainspring? My 861 Speedmasters feel very different from each other depending on whether a service is necessary - when they need a new mainspring, they feel a bit "mushy" when winding - whereas the well-serviced ones (and the brand-new 1861s) are nice and crisp.
     
  13. dx009 Apr 7, 2016

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    Yeah that's pretty much it. Either needs some servicing and/or oiling.
     
  14. Sgt_Bilko Apr 7, 2016

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    You hit the nail on the head with the word "mushy" and I was struggling to think how best to describe it. The Speedy just feels really smooth but precise. Actually no other watch winds as nicely.

    By contrast this De Ville feels a bit slack and mushy. It still keeps reasonable time and the reserve is solid but I suspect a service is overdue.
     
  15. Archer Omega Qualified Watchmaker Apr 7, 2016

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    Okay with the information given to me by PM I can answer a few questions...

    1 - Bezel is stainless steel on this one.

    2 - The case back seal is an O-ring, so this one is different from say the snap on backs used on the Speedmaster Dates with the 7750 movements that use a hard plastic gasket. The O-ring number is 088NS5029 - SEAL O-RING D29 D30.2 Ø0.6

    With regards to the feel of the winding, that's always a tough one. There are several things that come into play when talking about how the manual winding feels. It's not just influenced by the movement, but often by the crown and case tube as well. If the seal in the crown is particularly tight, it can change the way the winding feels, or even mask the feel of it from the movement.

    The winding feel of the crown I don't think would be influenced by the condition of the mainspring typically. The only place it might come into play (when it's not broken) might be right at the end as you reach full wind. If it feels sort of springy and not terribly definite there, it could be a sign that that tang end that is attached to the spring may be coming loose...

    Cheers, Al
     
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  16. abrod520 Apr 7, 2016

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    So as Al says, it may not be the mainspring - that was just the case with one of my 145.022s that felt that way. Still, I'd say you should get it serviced, one way or another!
     
  17. Sgt_Bilko Apr 7, 2016

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    There is no play with the crown in terms of lateral movement when winding. The winding becomes a little stiffer as the watch is fully wound and it can take around 80 rotations if it has previously stopped. There is a very definite clicking sound as it winds and just a slight push back if you release the pressure. None of that feels particularly wrong if you simply pick up the watch and try it but in comparison the Speedy has a smooth, precise feel that just glides.

    The De Ville has the later 18 jewel movement that was introduced in 93 and this would have been one of the very last 861's before the 1861 was introduced. Initially I wondered if this might simply be down to Omega having better quality control with the earlier 861 movements. I guess a service would be the right way forward.
     
    Edited Apr 7, 2016
  18. Stewart H Honorary NJ Resident Apr 8, 2016

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    When would you just "oil" a watch rather than disassemble it, clean it and lubricate it during reassembly?
     
  19. ulackfocus Apr 8, 2016

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    That's an easy one to answer: when you want to say "just serviced" in your eBay listing and all you have is a can of 3-in-1 oil.
     
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  20. Sgt_Bilko Apr 8, 2016

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    It's astonishing how many watches on eBay have "just been serviced" but they can't show a receipt for the work. I suspect many watches that are running really rough are simply given a drop of 3-in-1 to loosen them up or perhaps a bit of olive oil if that's all they have in the kitchen. Most of the time the "just been serviced" line is thrown in as a blatant lie.
     
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