# Vintage Tissot Seastar Navigator Chronograph.



## Defender (Jan 27, 2009)

I have a Seastar Navigator Chrono (manual with date), I trying to get the back off as I haven't since I got it to check on the condition and get the serial number to date it.

However this one has a 14 sided (Tetradecahedron?) raised boss on the back which is the only thing to grip on, what's the best way of opening it, I have the usual case back openers, but nothing to cope with this, thought about an adjustable spanner or similar, but there isn't much to grip on.

Many thanks,

Best regards,

Defender :astro:.


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## tixntox (Jul 17, 2009)

On my old one, I used a three pronged case opener with the flat inserts but it was a he** of a struggle as I don't think that it had ever been off before. Be very careful as it is very possible to damage the back or the lugs. I've seen many a one of these with the lugs snapped off! I love those watches by the way! Wish I hadn't let mine go! Would love to see it.

Mike


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## DMP (Jun 6, 2008)

I've heard that these things work a treat on most casebacks, so long as the caseback isn't on too tight. Never used one myself, though.

fleabay item 330398148041

If you end up getting one, would be interested to have your views on it

Cheers

Dave


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## Defender (Jan 27, 2009)

tixntox said:


> On my old one, I used a three pronged case opener with the flat inserts but it was a he** of a struggle as I don't think that it had ever been off before. Be very careful as it is very possible to damage the back or the lugs. I've seen many a one of these with the lugs snapped off! I love those watches by the way! Wish I hadn't let mine go! Would love to see it.
> 
> Mike


Hi Mike,

Thanks, I had thought about that method, it's not a 'minter' or anywhere near, but I don't to take any lumps out of the case back!










Image borrowed from 'net', mine sadly isn't in as good condition, but has the original Tissot 'T' bracelet and the dark grey dial with black register dials.

Best regards,

Defender :astro:.


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## Defender (Jan 27, 2009)

DMP said:


> I've heard that these things work a treat on most casebacks, so long as the caseback isn't on too tight. Never used one myself, though.
> 
> fleabay item 330398148041
> 
> ...


Hi Dave,

Yes, I have one of those, but in yellow, and have tried it, to no avail, it's worked on many other occasions, but not this time.

I'd not be without one, got mine from a stand at the Uxbridge Watch Fair.

Best regards,

Defender :astro:.


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## Agent orange (Feb 11, 2006)

I admitted defeat with my old one and took it to my watchmaker in the end as I didn't want to bugger it up.



















Lovely watches these Navigators. I'm assuming you know that it's a Valjoux 7734 inside. There's a list of Tissot movement numbers with their corresponding year of manufacturer pinned to this forum, once you're successful :good:

Cheers,

Gary


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## Defender (Jan 27, 2009)

Agent orange said:


> I admitted defeat with my old one and took it to my watchmaker in the end as I didn't want to bugger it up.
> 
> 
> 
> ...


Hi Gary,

Yes, I love these too, the 7734 is great, I wish my pair were in as nice condition as your minter?

I'll post up the date etc. once i get the back off!

Best regards,

Defender :astro:.


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## Agent orange (Feb 11, 2006)

My old one is long gone unfortunately, it acted a as part trade towards a Speedmaster 176.0012. It was in lovely condition and I do miss it, kept superb time too. Oh well you can't keep them all I guess.

Cheers,

Gary


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## Defender (Jan 27, 2009)

Right, after somewhat of a delay, I managed to get the back off without taking any lumps out of it either!

It is as expected a '7734 movement.

Where do I find the production code number to date it?

There are two numbers on the case back, one stamped five digit, the other 3 digit prefixed by a T and hand engraved.

All I can find on the movement it's self is SEVENTEEN with 17 Jewel right below it.

There is something else over to the right and above it, but it's so small I can't read it even using two loupes!

Could it be that the movements been replaced at some point?

I've also checked the case, but found nothing there either.

Can anybody advise me where else to look?

Best regards,

Defender :astro:.


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