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Cyma / Tavannes one-buton chrono

skridlov
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skridlov WRT Addict

skridlov

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I have just acquired this one - the price reflected the fact that the teeth visible in the accompanying close-up snap are worn and occasionally jump when setting. Otherwise it runs well. I was wondering whether there are any options for fixing this fault. So far I've been unable to identify the movement so sourcing a spare part (s) changes from difficult to impossible. I have some other reservations about it but I'll hold back on them for the moment.

Thanks!

Roy

 

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Cyma_chrono-5250006.JPG

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wls1971 Distinguished Member

wls1971

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The movement is a A.Michel S.A Grenchen usually just prefixed as A.M movements the teeth look not to be meshing correctly as opposed to excessive wear so more a problem with the setting lever than the wheels it looks like to me

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skridlov WRT Addict

skridlov

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Thanks. Could I have been more wrong? Quite possibly - I've had a lot of practice. Now I need to take a look at the setting lever - may be an easier fix than I thought. Are you absolutely certain about the movement? Not questioning you just interested in not having to be in any doubt.

And now that you've pointed it out, it's pretty obvious that the teeth aren't engaging fully - barely at all. How did I miss this? Same answer as above.

Roy

Edited by skridlov
lack of forethought
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wls1971 Distinguished Member

wls1971

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You have to do your research when dealing with watches of this vintage on the bottom plate of your watch there are 2 markings one is a triangle made up of a A and M so that tells me that its a Adolf.Michel movement, there is also a second symbol shaped like a shield this is a Ebauches Trust mark also know as Ebauches S.A which was a small group of movement manufactures who in 1926 set up a partnership to pool resources in developing movements in order to survive against larger manufactures Adolf.Michel was one of the founding members of that group, the mark on your watch was fairly short lived and ran from 1936 to around 1939 so your watch movement dates from that period.

It looks like a calibre 237 from the dial side so you need to measure the width of the movement and confirm its a 12 ligne movement if so that would make it a calibre 1710 finding info on watch movements of this vintage is very hard finding parts is almost impossible, for a positive identification you will probably need a Bestfit book to check but you have been given enough information for you to do your research.

Other things I can tell you about your watch are that it is a British military issue watch issued by the Hydrographic Service  to the Fleet Air Arm so you maybe better doing more research along those lines, I think I have a reference book with this watch in, but I am at work at the moment so will look tomorrow when I get home,

Wayne

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skridlov WRT Addict

skridlov

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Thanks Wayne, a detailed and painstaking contribution.

I'm not entirely green when it comes to identifying movements - I have a Paulson catalogue and use the Ranfft site plus the usual web searches. I was misdirected a bit as my friend with whom I jointly buy and sell stuff was adamant about it being a Cyma. Strange how that sort of certainty can prevent one from starting from a blank page. There was another person keen to buy it who was equally certain and, it seems, equally in error!

Thanks again

Roy

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wls1971 Distinguished Member

wls1971

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And here's another one marked Pontiac, but with the addition of shock protection the seller also states that this movement is a Venus/AM, Venus where also members of Ebauches S.A it could be that Venus assigned there own calibre number to the A.Michel supplied Ebauches.

http://www.lamesuredutemps.com/one.cfm?Supportchoc&uuid=E278E9E8-01FE-5E41-8264B9B7B15B414D

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