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Discussion Starter #1
.....and their movements - swapping possibility.

Suppose you have a 600m quartz tuna. It beats with a 7549-7009 quartz heart.
Now, if by any chance, someday that movement happens to die on you (afterall, we're talking about a watch that has 30+ years).....would a 7C46 quartz heart be a direct fit inside this vintage quartz body (golden tuna 600m)? How would that goes regarding 7549-7009 dial and hands fitting on a 7C46? Are we talking about complex transformations to be performed, in case of both movements are not a direct swap?
For example, I would have the 7549-7009 600m dial fitted to the 7C46 movement, and 7C46 300m hands installed on it (they are 98% similar in appearance to the original 600m quartz hands).

Do you guys, experts in tunas, think that would be possible? Still, if I insisted on the original 600m quartz set of hands, what modifications (if any) would have to be performed in order to fit them to a 7C46 caliber?

Thank you all for any inputs.
CHRIS
 

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The 7549 is special, and will fit only 7549 hands, or 6306/9 hands. However, I just replaced the entire green circuit block (including coil, circuit etc) from a 7546, and confirmed the same part from a 7548 is a drop in replacement. As this is the part which is most likely to die, this should answer your question.
 

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Discussion Starter #3
Hi, Harry. Thanks for the response.
Yes, you answered part of my question - about the unswappability of the 7549 hands. Also, the 7548 movement parts are a possible option.
But still, the reason I'm asking this is my intention to count on a modern and plenty available movement, as the 7C46. Now I know that 7549 hands won't work on the 7C46. But could I still have this combo: 7C46 movement/7549 600m dial/SBBN007 hands - all assembled together and fitted inside the 7549-7009 600m case?

Would like to hear opinions especifically about this last part. Thanks.
CHRIS
 

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Hi Chris - yes, as far as I know that is a direct swap - I'm sure someone will be able to confirm this...
 

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Harry said:
The 7549 is special, and will fit only 7549 hands, or 6306/9 hands.
If it fits 6306/9 hands then it will also fit the overwhelming majority of seiko hands used in mechanical calibers, both vintage and modern.
 

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Isthmus said:
If it fits 6306/9 hands then it will also fit the overwhelming majority of seiko hands used in mechanical calibers, both vintage and modern.

Indeed, I should have clarified that it is "special" in that it won't fit the other 7c46 Tuna hands!
 

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Discussion Starter #7
Thanks guys - Harry and Gabe.
So although Harry has pointed me in the direction of a possible swappability of calibers in the 7549-7009 case, I'd really like to have some confirmation of someone who have already tried this - 7549-7009 dial + 7C46 300m HANDS + 7C46 MOVEMENT dropped inside the 7549 600m case. That would be good enough for me.

Also, still about the 7549-7009 caliber....sometimes the date don't fall squarely inside the dial window. What part of the movement is responsible for this feature, and also why does it happen so frequently on this particular caliber?

Thanks everyone. 8)
 

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Ok, here is what I think of it.

Hands of the 7549 will only fit the 7549 models, the hand sizes are so uncommon (read big) that they will only fit this movement.

The dial of a 7C46 movement will not fit a 7549 movement, the center hole needs to be bigger for that.

The dial of the 7549 will fit the 7C46 movements but the center hole is bigger as neccessary, could case a little bit of "seethrough" between hands and dial.

The stem of both movements are imo identical, if not it will be no problem as these divers have a 2 piece stem and you can swap the movement piece of the stem.

Crown locations on the watches are identical, so that should work also.

So, a 7C46 with old dial and SBBN007 hands....should work.

At this moment I can't say if this movement will fit the case in diameter or the fitting of the stem in terms of hight on the movement.
I think it will fit as the cases of most tuna's are more or less identical but can't be 100 % sure
 
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