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On My Bench - Seiko 7549-7010 Deconstructed

  1. JimInOz Melbourne Australia Feb 16, 2021

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    Here we have a Seiko 7549-7010, AKA the "Tuna Can" in component form.

    Edit: It has been bought to my attention that this is NOT a Baby Tuna!

    Hi Jim,

    Saw your On My Bench post for the 7549 ( 47mm diam) and noted you referred to this watch as the "baby tuna"

    Whilst it's a baby compared to the original grandfather tuna (50.5mm diam) I've always associated the "baby tuna" with the 5M23A series which had a plastic shroud and 43mm in diameter.

    The 7549 was the first professional 300m quartz diver ever produced and because it had the silver metal shroud was nicknamed "Tuna Can"

    Interested to see if any other WIS pick up on this.


    So the introduction has been updated accordingly.

    IMG_5493.JPG

    Not much different to the one I just completed except for the case design, which I'll get to later.
     
    Edited Feb 16, 2021
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  2. Scarecrow Boat 5000 Candles in the Wind Feb 16, 2021

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    I have to say, your "On My Bench" series are some of my favorite threads on this forum to read through. Thank you so much for the time you put into writing these up and the pics you create for them. As someone that loves taking things apart, I enjoy living vicariously through these posts :thumbsup:
     
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  3. JimInOz Melbourne Australia Feb 16, 2021

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    I'll see if I can keep you entertained then ;).

    First step was to remove the bezel shroud. Held in by three screws, it requires the screwdriver with the correct tip. Us a standard Phillips head and you risk deforming the slots in the screw head. I use JIS (Japanese Industrial Standard) screwdrivers on any screw coming from Japan, from motorcycles all the way down to watches.

    IMG_5447.JPG

    Note that I'm doing this part in my garage on a clean hand towel.
     
  4. JimInOz Melbourne Australia Feb 16, 2021

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    With the bezel shroud off, we can see the gunk and corrosion that has built up over time.

    IMG_5448.JPG

    With the shroud off, I can clean the case to prevent "detritus" getting into the case when I open it. I think it needs it!

    IMG_5450.JPG

    IMG_5452.JPG

    IMG_5453.JPG
     
  5. JimInOz Melbourne Australia Feb 16, 2021

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    So here we go, cleaning time.

    IMG_5455.JPG

    Most of the cleaning will be done around the caseback using a soft brush and a softwood stick.

    IMG_5454.JPG

    With the case now clean enough to open it can go back into the watch room. Sure can't stay here!

    IMG_5456.JPG
     
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  6. JimInOz Melbourne Australia Feb 16, 2021

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    Caseback comes off.

    IMG_5457.JPG
     
  7. JimInOz Melbourne Australia Feb 16, 2021

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    And then it all happens as described in the other threads.

    MovStrip.gif
     
  8. JimInOz Melbourne Australia Feb 16, 2021

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    With all of the movement parts safe and sound I can turn my attention the the case.

    After removing the bezel, I found even more crud.

    IMG_5465.JPG

    So it was back to the garage to clean it up so I don't get gunk all over my casebook tool.
     
  9. JimInOz Melbourne Australia Feb 16, 2021

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    A quick change of pins on the caseback tool..........

    IMG_5466.JPG

    and the remainder of the case was disassembled.

    IMG_5467.JPG

    The nylon glass fixing gasket (red arrow) was so old it disintegrated, so I'm waiting on a replacement from the US.
     
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  10. JimInOz Melbourne Australia Feb 16, 2021

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    The bezel was soaked overnight in mild soap solution and then I started cleaning the bezel notches using my "bezel holding jig".

    IMG_5470.JPG

    One notch at a time.

    IMG_5479.JPG

    Next I'll clean the case, but first I'd better change the wash fluid :eek:.
    Note all the crud that gets removed and won't pollute my ultrasonic solutions when I clean the parts (except the bezel).

    IMG_5487.JPG
     
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  11. Jones in LA Isofrane hoarder. Feb 16, 2021

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    watchcollect and JimInOz like this.
  12. JimInOz Melbourne Australia Feb 17, 2021

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    Time to gather up all of the bits and get them ready to clean.
    Into the basket they go.

    IMG_5494.JPG

    and off for a nice bath in my vintage cleaning machine.

    IMG_5498.JPG


    While that was happening, the case was cleaned by hand again, then given an ultrasonic bath.

    Came up quite well I think. Just a few tiny corrosion pits left, but I don't think it's worth me buying a laser welder.

    CaseDone.gif
     
  13. JimInOz Melbourne Australia Feb 18, 2021

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    Things on hold ATM, waiting for parts, so I'll just post random pics.

    BattLeak.jpg
     
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  14. JimInOz Melbourne Australia Feb 18, 2021

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  15. JimInOz Melbourne Australia Feb 18, 2021

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    I noticed the stem extension wouldn't sit correctly.
    It appears that a substitute spring was fitted and the top coil hadn't been flattened, just cut, so the stem washer was seated at an angle.

    I put the spring on a 1.0mm dial pivot wire in a lathe collet and used a Dremel wheel to face the spring.

    This resulted in an improvement in alignment but also in a loose joint.

    StemSpring1.jpg

    Rather than try to source a replacement spring, I went to the spares and got another stem washer to remove the slack in the connection.

    StemSpring2.jpg
     
  16. JimInOz Melbourne Australia Feb 25, 2021

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    How long does it take?

    I guess there's a reason for huge packages waiting for a cargo slot, but my tiny package?

    Screen Shot 2021-02-25 at 21.20.18.png


    I don't like to have more than one watch at a time on the bench (not as organised as @Archer, @ChrisN et al ;)) so we just patiently wait for the postman to cometh.
     
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  17. dsio Ash @ ΩF Staff Member Feb 25, 2021

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    I think the logistics is the bit that brings a lot of independent watchmakers a bit unstuck when they’re working on their own, its the un-fun part that starts to really eat your time when you begin servicing a lot of pieces.
     
  18. JimInOz Melbourne Australia Feb 28, 2021

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    Almost here ::psy::.

    Screen Shot 2021-03-01 at 16.09.11.png
     
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  19. JimInOz Melbourne Australia Mar 4, 2021

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    Only took FIVE DAYS to get from Sydney to Melbourne :rolleyes:.

    JB_Delivery.JPG

    Oh well, enough complaining, time to get back to work on this one and hope there's no more overseas parts need next time.
     
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  20. JimInOz Melbourne Australia Mar 6, 2021

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    And just when you think you can crack on with it, family issues interrupt.
    But my impatience is nothing compared to CAT scans, MRIs, lumbar punctures, brain surgery and the rest of the things that go with all that.
    :(

    Anyway, I managed to get back to it today so I got the case ready for the new crystal.

    ReadyForXtl.JPG

    The edge of the new crystal has to be carefully lubricated so that only the tiniest hint of silicone is present on the lower edge. In fact, the edge is wiped with a chamois pad after lubing so there's no chance of excess lube going anywhere. The crystal is now pressed in by hand and checked for correct seating in the gasket.

    CrystalSet.JPG

    Next step is to fit the nylon gasket into the step on the side of the crystal. It's used as a bearing surface so that the steel crystal ring doesn't graunch the crystal as it gets tightened. That done, the screw down ring is fitted and finger tightened, and then it's over to the other bench to tension it down.

    CrytalLocked.JPG

    Lastly, the crown is fitted and the caseback seal is lubed and fitted and the casebook installed and tensioned.

    CasebackFit.JPG

    Then a water tightness test is performed.

    WP_Test.JPG

    No bubbles were evident under the heaviest vacuum I could manage with my "tester" and a condensation check showed no water on the crystal.

    I really need to get myself a proper waterproof tester though.
    Raiding the kitchen cupboards for "tools" gets me some funny looks from Ms JiO :D.
     
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