Seiko 7s25C Disassemble and Assemble Project

[adiorio110]

This is my first wrist watch tear down and rebuild.

My usual course of action is to take a movement apart in stages and rebuilding, going deeper each time I tear it down. I have taken down the watch to the point of removing train and the complete mainspring barrel. When powering down the mainspring the screwdriver slipped and the spring unwound a little to fast.,I  checked it and it seems fine. When rebuilding the watch I wound it using the screw driver to test the train and pallet. all functioned well. Problem is when I release the click The mainspring does not unwind anymore. I am confused because the hairspring is moving and getting power.  Where may I have gone wrong?  

 

Anthony

Edited March 22, 2017 by adiorio110

[clockboy]

When the pallet is moved & the escape wheel turns then there is some power in the train of wheels. Strange that the barrel is not unwinding when the click is released. Perhaps the spring is not fully winding in the barrel and slipping before fully wound. 

[anilv]

Hi Adiorio,

On most automatic watches, the AutoZone will prevent the barrel from unwinding. On these Seikos, you would need to remove the intermediate winding wheel .. the wheel which is secured by a screw with 3 lines. This is a left-handed screw so you have to turn clockwise to remove.

Anil

[adiorio110]

 

8 hours ago, clockboy said:

When the pallet is moved & the escape wheel turns then there is some power in the train of wheels. Strange that the barrel is not unwinding when the click is released. Perhaps the spring is not fully winding in the barrel and slipping before fully wound. 

That was my thought at first but when I remove the second reduction wheel while holding back the mainspring barrel it would then unwind.

32 minutes ago, anilv said:

Hi Adiorio,

On most automatic watches, the AutoZone will prevent the barrel from unwinding. On these Seikos, you would need to remove the intermediate winding wheel .. the wheel which is secured by a screw with 3 lines. This is a left-handed screw so you have to turn clockwise to remove.

Anil

I guess we are talking about same wheel I know it as the  "second reduction wheel" . Thing that confuses me is the first time I thought the reduction wheel was in place. I probably had it removed and forgot. After reviewing Marc's video I see you are absolutely correct. 

Well I guess all is good then. On to the next stage. 

Thanks Guys

Regards

Anthony

[adiorio110]

I have now taken apart and rebuilt the 7s26c 3 times, dry runs no oiling, I like to get the mechanics down first  The first time out I broke the plastic day date collector wheel. Dman2112 was so kind as to donate the part as soon as it gets here I will tear it down again and oil it. 

[ricardopalamino]

Hi , are you working on a 7S25C and a 7S26C both . I saw you have 2 posts and you use both calibers . The date part # you show is similar but different for both calibers .

In any case as I read this post it sounds as if you have proceeded correctly so far .  In checking the train wheels for free movement , remove the autowind bridge and parts as mentioned above .  Also at this point , I have not installed the pallet fork or balance which allows me to turn the mainspring with the screw , [click installed or not ] , to see the free movement of the train wheels as the mainspring winds down .

I have attached an article from N.Hacko's website that shows the rebuild for the 7S26 for amateurs . I used this article for a guide when I first got started .

http://www.clockmaker.com.au/diy_seiko_7s26/

[adiorio110]

4 hours ago, ricardopalamino said:

Hi , are you working on a 7S25C and a 7S26C both . I saw you have 2 posts and you use both calibers . The date part # you show is similar but different for both calibers .

In any case as I read this post it sounds as if you have proceeded correctly so far .  In checking the train wheels for free movement , remove the autowind bridge and parts as mentioned above .  Also at this point , I have not installed the pallet fork or balance which allows me to turn the mainspring with the screw , [click installed or not ] , to see the free movement of the train wheels as the mainspring winds down .

I have attached an article from N.Hacko's website that shows the rebuild for the 7S26 for amateurs . I used this article for a guide when I first got started .

 

4 hours ago, ricardopalamino said:

http://www.clockmaker.com.au/diy_seiko_7s26/

 

Good Catch..Sorry  I am working on the 7s26C The title was a typo, a result of short fat fingers. I have to watch that I'll be causing more confusion than anything.

I also used the guide from N Hacko, Very informative. The man did a GREAT job documenting the process. 

[ricardopalamino]

OK , sounds good . You probably have the attached tech sheet . I've attached it anyway in case you or anyone needs it . 

7s26-36Ctech.pdf