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Discussion Starter #1
Hi all , I just got this Tissot Seastar that was in a drawer for 30+ years and I want to service it . I did a little research and found out that it is a front loader where I have to remove the crystal to remove the movement . I was able to remove the crystal and I read that there is a "C" ring I have to remove to get the movement out....so far , so good . Now I'm kinda stuck as I couldn't find any instruction past this point .
I read somewhere that there are no dial feet or case screws for the dial ??
Do I remove the hands and try to lift up the dial and then loosen the stem screw to remove the stem and crown ?
Any Help is appreciated...Thanks , Louis



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Usually one-piece case designs (including OceanStar) offer a stem release accessible from the dial side. However, they may also be "keyed" two piece stems (the movement will drop out when the crown/stem is turned to a position allowing the male key to slide dialward out of the female key). Then there are two-piece stems that "snap" together...these require that you pull with considerable force on the crown to "unsnap" the outer (usually female) stem from the inner (usually male stem)...the first time you do this on a Patek Calatrava it can be a real heartburn moment.

The Tissot 781 and 783 movements use a friction grommet to retain the dial foot. So assuming you have the 783, once the hands are removed, the dial should lift off. The dial feet should be very close to "4" and "10"...so alternately lifting gently at both should easily free the dial.

Note that Jules Borel list these stems for the 783:
-STEM, 200/1538FDiscontinued - Use 401/470
-STEM, (DRESS) 1106/OME 1480 6.40
-STEM, TAPERED SHLD (SEA STAR) 401/1/TIS 782 14.60
-STEM, TW0-PIECE (BOTH) 360/459Discontinued

So you might want to try turning the crown first and see if you find a position where the movement will drop out. Alternatively, remove the hands/dial as above then lift the set lever to release the stem (assuming it is one-piece).

Regards, BG
 

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Discussion Starter #3
Thank You BG for a lot of useful information on this . Now I have a place to start the removal . I have not seen a stem release like the Seikos..as a mater of fact I can not see past what looks like a white ring around the dial ...Maybe a dial ring ?
The Info about possible friction grommets and the possible location of the dial feet is really valuable....I don't want to bend or warp the dial by prying in the wrong place .
I will wait a day or two before I begin in case anyone else has any input. I don't want to mess up a watch that has been waiting 30+ years to get into my hands .

Mahalo , Louis
 

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Discussion Starter #4
More help from another forum...

Andyclient
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72 posts
LocationSuffolk
Posted Today, 01:14 AM
I can't remember where i found it apart from the Net when i attempted one of these, I have mentioned it before on this forum but couldn't find the article to back it up .
But the procedure that i had read , was that you remove the crystal , that is what the tool no refers to on the case , but a crystal lift will do the job as you know.
remove the hands , then the dial , the dial feet are not held in with retaining screws as is the norm and are friction fit as mentioned already.
On the one i did and the one that was in the walk through that i can no longer seem to find you had to remove the calender works then the keyless works to then remove the stem and then the movement can be removed from the case

You don't have a calender complication so it will just be a case of remove the keyless works to remove the stem and the movement will come out
 

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well i am very curious myself....looks like a beautiful watch...
 

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Discussion Starter #7
Got 'er Done....

Thanks to member "Bench Guy" I had a clue on how to proceed to get the movement out of the case . As a matter of fact he was spot on. After removing the crystal and "C" retaining ring I gently levered the dial off . The dial feet were at the 4 and 10 position and are a friction fit held by 2 plastic or nylon grommets located in the base . I disassembled the setting mechanism to remove the stem and crown and the movement was ready to come out. The dial ring gave the movement a comfortable fit in the case...similar to a movement ring on some watches . When I refit the stem and crown ,I refit the movement and just pushed and turned the stem/crown in after a service lube on the stem . It went in smooth as butter and engaged the setting lever .
I discovered that the movement is a 781-1 caliber and the serial # dated it as a 1969 model...both numbers were stamped on the movement .


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wow...that is great work and great Bench Guy was willing to walk you thru it....that is a real beauty....i love it ...
 

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Discussion Starter #9
Thanks John , I found a generic replacement crystal with tension ring on the bay but I tried polishing the original first , with satisfactory results .
I use 2000 grit sand paper with a dab of automotive rubbing compound sprinkled with water to remove any scratches . I use a figure 8 motion like you use to polish fiber optic glass . Then I use diamond paste w/oil to polish with my dremel .

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