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Discussion Starter · #1 ·
hello to all... i'm new - and it was suggested i try posting this here ... i have some questions - need the experts...

so.. maybe this is the better - correct headline, forum, whatever it's called here...

i just got back a slightly damaged seiko skx173.. with a 7s26c...all original.. and very 'clean'.. manu 2017 yr.. it was 'jammed' not running.. the person 'claimed' they dropped it ..???.. opened it up - found the 3 slotted screw/nut to the secondary reduction wheel and that wheel - off - rolling around free..the screw/nut looks as if there is no threaded shaft to screw into the bridge plate.. the wheel looks like the very edges of some teeth are slightly 'blunted' vs sharp point..i cannot see the broken shaft in the 'riser tube'.. or anywhere else..??
so - with that - (my 1st time)
i released the spring pressure on the ratchet wheel & removed it.. loosened the bridge screws slightly - cut a thin strip of white paper and slid it just enough to view it passing underneath.. so - the tube/furrel/rotor post -(learning all new correct terms) is not blocked - no obstruction - i can see the paper sliding under..
not having a left handed screw - though the ratchet wheel screw is just about the same dia - wrong thread - poss same length - i get a better idea of what maybe is the size and length of wheel 2 nut.
taking a small pin - and sliding it into the ratchet post - as a reference - to 'feel' the threads and resistance as a base line - i'd say my 2nd wheel post is approx 40-60% - threads, depth, count, defined and not completely 360 degrees - so it has suffered some damage by the sneaky person who pretended not to know what happened..
i get that the tube/post is pressed in - but it might be easier to just get a bridge plate - then new 2nd wheel to be safe - and screw/nut.. or 2 .. if ..if - i find that the existing post is 50% stripped out with the first nut install- and i'm not getting a good secure 'grab' - then it's plate changing time..
of all the pics online - none depict how long that shaft is on the screw/nut.. and since i don't have a complete one .. i'm guessing at the logical steps to a solution.

i'd prefer to simply obtain a newer bridge plate assembly with the first reduction wheel, pawl, secondary reduction wheel and poss main ratchet wheel? attached and in like new condition - so i could easily swap them out as an assembly/unit.. vs - swapping each piece.. or a new 7s26c movement - plus date day wheels, dial, hands ..
i should mention - after making sure nothing else was 'loose' or 'floating around' - i wound it by screwdriver - and its been working fine for days.. runs a bit fast - but i 'tuned it' a bit - now it's like 3 min fast per day - which i can refine after swapping out the 'auto winding' parts section..just wanted to ensure everything else was 'normal' and working - it appears to be - as best as my limited knowledge can tell.. i do need some real magnification though.. i thought the ipod nano was small..
so - it's help time..
... anyone have this assembly.. or direct me to or offer up where i could get a newer 'clean' one..( 7s26c )
otherwise my options (in order) - locate each part - new and a hubble to see what i'm doing - but pricing is close to a new movement.. not good.. a new 7s26c and do the swap -mvmt - to keep it all original (value wise).. or nh36 plus more parts and either steal from 7s26 or add to the parts list and it runs like it did before - but lost it's OEM value - esp for being 5 yrs old and in excellent if not better condition..
open for your input.. excuse me if i keep using the wrong terms..
and thanks for the feedback .. i totally enjoy learning and being pointed in the 'smart' direction

thanks
jp



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Craftsman
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First, I would provide a more complete set of pictures showing the bridge and other parts you have removed from the movement. You state the watch was dropped and something jammed. Does that mean it would not wind via the rotor? Download the Seiko technical guide for 7S26 and look at the parts names in the schematic and reference that to the parts list for part numbers. Do a search or ebay or other sources for the Seiko specific parts you might need or place a WTB ad in the trading section here and someone may be able to help you with the specific part needed. The 7S26 is a widely used movement and parts should be readily available for repairs.

Glad you have the watch running and keeping good time but that is not necessarily indicative of the watch running properly. You really need to look at the movement function using a Time Grapher to determine proper movement function. Think of it like an engine diagnostic tool used in automobiles.
 

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Discussion Starter · #3 ·
yes.. you are correct - and i've incl some below.. as best as i could - without removing the ratchet wheel, 2nd wheel, etc to expose the bridge plate.. i never completely removed the plate - just loosened it enough to slide a pc of paper under - like one would do to check a barrel..
and yes - i was 'told' the watch was accidentally dropped - and then it wasn't working.. upon return to me - it was stopped (could have been out of winding power also).. i did not attempt to 'shake it' or play with it .. i simply refreshed my studying of these - and then opened it up. i didn't take any pics immediately - but the rotor was intact, everything else seemed solid - but the 2nd wheel and screw/nut cap were floating along the edge - obviously being broken (however) and fell free.. upon careful exam and then removal of the mvmt - everything else appeared intact.. i reassembled and gave it a quick hand wind - it ran overnight - fast 10 min.. next time i opened it up was to loosen and really look - now that it ran.. and then the paper and pin probe (lacking a microscope)
between yest and today i tweaked the adjustment again - now i'm down to 1-2 min fast - day and date changed as it should..
i cannot find any visible damage to the outer case - or marks on the back or opening slots.. i can't say what really happened, and the screw cap - has no screwdriver hack marks.. so..??
and yes - i did download the parts list for this 7s26c.. i may misuse a part name if i cannot find it - but i'm localizing my issue to this area.. so..
i can find the screw/nut and the 2nd red wheel.. not the bridge plate.. and def not that tube/shaft that the 2nd wheel rides on.. though i know which one to 'steal' from a donor plate - though rather just use the new plate.
and yes - there are plenty of these out there - yet only 2 'c' versions i could find so far - used/dead - which means they may have the same issue and pricing is like half of an entire new mvmt..
i didn't know about the buying parts bit here.. thanks for that..
though if this were my regular hobby - for these little parts - i'd simply donate them to whoever.. not like it's an entire working mvmt i could make a watch from..
and yes - thanks again.. i know that once i get this running - if it seems sound and 'normal' then yes - it will need a trip to the specialist - cause i'm not - for a clean, lube, and tune.. not thinking it makes sense until it's actually is up and running.. plus i want to learn and do this work - for me - as a step towards building one from scratch just to be different and know i did..
i'll have to find that 'trading section'...
i really like all the knowledge and input... like a few of the other hobbies - always good when everyone there is open to support and assist vs ego and selfishness..
thanks..
jp
 

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Discussion Starter · #4 ·
yes.. you are correct - and i've incl some below.. as best as i could - without removing the ratchet wheel, 2nd wheel, etc to expose the bridge plate.. i never completely removed the plate - just loosened it enough to slide a pc of paper under - like one would do to check a barrel..
and yes - i was 'told' the watch was accidentally dropped - and then it wasn't working.. upon return to me - it was stopped (could have been out of winding power also).. i did not attempt to 'shake it' or play with it .. i simply refreshed my studying of these - and then opened it up. i didn't take any pics immediately - but the rotor was intact, everything else seemed solid - but the 2nd wheel and screw/nut cap were floating along the edge - obviously being broken (however) and fell free.. upon careful exam and then removal of the mvmt - everything else appeared intact.. i reassembled and gave it a quick hand wind - it ran overnight - fast 10 min.. next time i opened it up was to loosen and really look - now that it ran.. and then the paper and pin probe (lacking a microscope)
between yest and today i tweaked the adjustment again - now i'm down to 1-2 min fast - day and date changed as it should..
i cannot find any visible damage to the outer case - or marks on the back or opening slots.. i can't say what really happened, and the screw cap - has no screwdriver hack marks.. so..??
and yes - i did download the parts list for this 7s26c.. i may misuse a part name if i cannot find it - but i'm localizing my issue to this area.. so..
i can find the screw/nut and the 2nd red wheel.. not the bridge plate.. and def not that tube/shaft that the 2nd wheel rides on.. though i know which one to 'steal' from a donor plate - though rather just use the new plate.
and yes - there are plenty of these out there - yet only 2 'c' versions i could find so far - used/dead - which means they may have the same issue and pricing is like half of an entire new mvmt..
i didn't know about the buying parts bit here.. thanks for that..
though if this were my regular hobby - for these little parts - i'd simply donate them to whoever.. not like it's an entire working mvmt i could make a watch from..
and yes - thanks again.. i know that once i get this running - if it seems sound and 'normal' then yes - it will need a trip to the specialist - cause i'm not - for a clean, lube, and tune.. not thinking it makes sense until it's actually is up and running.. plus i want to learn and do this work - for me - as a step towards building one from scratch just to be different and know i did..
i'll have to find that 'trading section'...
i really like all the knowledge and input... like a few of the other hobbies - always good when everyone there is open to support and assist vs ego and selfishness..
thanks..
jp
oops .. forgot the pictures.. ha..
 

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Craftsman
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You do not say if the screw that was loose is broken or not. If it is intact, remove the rotor. The loose transmission wheel you have goes gear down and engages the with the ratchet wheel. The ratchet wheel is where you wound the movement manually with a screw driver. Place the transmission wheel on the exposed post so the it engages with the ratchet wheel. The pawl lever arms need to go on either side of the transmission wheel and drive it’s motion through the winding weight to wind the mainspring. The screw should go through the top of the transmission wheel to secure it to the bridge. Good luck with it.


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Discussion Starter · #6 ·
You do not say if the screw that was loose is broken or not. If it is intact, remove the rotor. The loose transmission wheel you have goes gear down and engages the with the ratchet wheel. The ratchet wheel is where you wound the movement manually with a screw driver. Place the transmission wheel on the exposed post so the it engages with the ratchet wheel. The pawl lever arms need to go on either side of the transmission wheel and drive it’s motion through the winding weight to wind the mainspring. The screw should go through the top of the transmission wheel to secure it to the bridge. Good luck with it.


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sorry for the confusion . i thought i incl the picture and addressed that detail..
to fill in - the 'pinion' (screw/nut) for the 2nd reduction wheel was off - no threaded shaft, along with the 2nd wheel - just rolling around in there loose.. upon my opening this up.. i do not know where the shaft piece is, can't see it or find it.. after examining the 2nd wheel - i put it into position - with the pawls and held it down with the head of a pin and manually rotated the 1st reduction wheel to make sure everything meshed and worked - it does.. i just don't like the look of some of the teeth edge on wheel 2 - hence replace it.. as for the missing shaft - the paper trick to verify it's not in there.. the pin to check the threads - no microscope or new pinion nut - yet.. but i did remove the loose wheel - and then wound it by screwdriver --
so - it is running - by physically having to wind it - so i can see if and how it runs - before scraping the mvmt completely .. not sure if this is correct - but logically -to me- all steps towards a solution..
i'm sure you all have far quicker, better, faster, more thorough methods - but this is me - new to this - and using limited knowledge to problem solve.. hence - learning..
if the 2nd wheel pinion nut is close to the same size length as the ratchet screw - then i think i would have found it inside - or it would have interfered with this thing running now for the week - and every 24-36 hrs i fine tune the adjustment to get closer to accurate time keeping.. each time it only gets closer - never the adverse..
after watching many videos of disassembly and rebuilding - i'm pretty sure that piece isn't in there ..it should have been stuck in the tube/axle.. but the half piece missing, the lightly damaged threads and slight marks at the top of the tube suggest a diff story is closer to the truth than the one i got..
i'm really surprised with the commonality of this issue - that no one has made a detailed video - with extreme close-ups - for people like me.. i would except i don't have the cameras to do this, nor all the correct tools, and i certainly wouldn't want to lead someone else down a vague or misleading path.. but i will detail this for anyone who wishes to read and is seeking one point for the info and fight to fix this.. all of course with everyone's input ..
i'm hoping someone will catch this ( as sourcing the correct parts is .. challenging) and say hey - i'll tape them to a card and mail it to you - as long as you use them and get it back up and running.. i'll do the work - then get it metered.. and then offer up the logical path for everyone else - esp beginners like me - who want to get into this but are hesitant about their abilities..
thanks..
jp
 

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Craftsman
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I have not looked at a 7S26 in a while. Two questions. 1. The loose screw. Does it have three slots across the top of it or a single slot like a standard screw? If it has three slots across the top, it is a left hand thread screws which means you must turn it counter clockwise to tighten and clockwise to loosen. If it is indeed a left hand threaded screw someone may have tried to loosen it like a standard screw and broke the head off the screw. Something to be on the lookout for if you plan to work on watches. Not always the case as some Swiss movements use a standard single slot screw but the screw will be left hand thread on at least one of the screws for the automatic works crown wheel or ratchet wheel. 2. Are there still threads visible in the bridge screw hole where the transmission wheel resides. If that hole is stripped of threads, you will likely need to obtain a new bridge and also the screw to hold the transmission wheel. You can search ebay for 7S26 or a watch with this movement for parts or repair.
 

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I'll jump in, I appreciate the OP is hoping to troubleshoot and do the work as an exercise and for the pride involved. I commend you !

That said a brand new 7S26C is about $60 all-in and will go for 20+ years straight out of the box. So don't go buying a used 7S26C powered donor watch no matter what the price was, if going for a movement swap get a new one. You can re-use the day of week wheel from the one you have now if the new one comes set up for the other crown position ( 3 vs 4 o'clock) or no day wheel at all, which is how Seiko sells them.

Good luck !
 

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Discussion Starter · #9 ·
I have not looked at a 7S26 in a while. Two questions. 1. The loose screw. Does it have three slots across the top of it or a single slot like a standard screw? If it has three slots across the top, it is a left hand thread screws which means you must turn it counter clockwise to tighten and clockwise to loosen. If it is indeed a left hand threaded screw someone may have tried to loosen it like a standard screw and broke the head off the screw. Something to be on the lookout for if you plan to work on watches. Not always the case as some Swiss movements use a standard single slot screw but the screw will be left hand thread on at least one of the screws for the automatic works crown wheel or ratchet wheel. 2. Are there still threads visible in the bridge screw hole where the transmission wheel resides. If that hole is stripped of threads, you will likely need to obtain a new bridge and also the screw to hold the transmission wheel. You can search ebay for 7S26 or a watch with this movement for parts or repair.
yes - the 2nd wheel pinion /nut has the 3 slots - and is left hand thread - and was one of the 1st things i noted while studying the videos.. usually when 2 or more drives are working in unison - one will be opposite to counteract torque..
and as i detailed - there wasn't any 'shaft' left in the tube - hence the 'paper' trick.. nor was it insde the case - my guess - the story i got wasn't actually the truth - and someone broke this - or at least tried to hide whatever by removing the broken shaft.. obvious by the light tool marks on top of the tube and by my 'sensing' the threads depth and corse-ness by lightly probing with a pin and feeling each thread.. again - i had inc this detail for full info..
i know i can swap out a tube - but being that small - prob no more diff than swapping out the plated and dealing with that clip on 1st red wheel shaft - so.. better to swap plate and be sure the new 'tube' is set at 90 degrees so the 2nd wheel runs truer..
 

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Discussion Starter · #10 ·
I'll jump in, I appreciate the OP is hoping to troubleshoot and do the work as an exercise and for the pride involved. I commend you !

That said a brand new 7S26C is about $60 all-in and will go for 20+ years straight out of the box. So don't go buying a used 7S26C powered donor watch no matter what the price was, if going for a movement swap get a new one. You can re-use the day of week wheel from the one you have now if the new one comes set up for the other crown position ( 3 vs 4 o'clock) or no day wheel at all, which is how Seiko sells them.

Good luck !
and a big thanks - for jumping in.. it's a personality trait - i refuse to be beaten.. and if intrigued - then i need to understand it and learn it.. something about these - going thru the videos - got me.. i'm determined to build myself a custom something... maybe a sleek modern sub.. or a subdued monster.. not sure - maybe a scaled down version of one as i don't think a 2.5" hunk of metal works on a normal size wrist.. ha..
and i'm in agreement with you -- though i will say - i am not sure where you all source these mvmts and parts for the prices stated.. i'm good at research and sourcing - i keep coming up with 80 - +-5.00 not incl ship n tax and then there are all the 'related' pieces required - depending on which path 7s26c easier & less expensive and original.. vs nh36 and add on more parts or steal some of mine - more money and not original any more > value if i choose to sell after i build my custom 'toy' .. i am not rich.. so...
but i def agree with the 'donor' mentality.. a bridge plate from a very clean unit - for a swap - worth the shot.. anything further or a dirty corroded or otherwise compromised 'donor' = waste of time as it could be worse i minute down the road in my watch.. that's like touching the stove twice..
just thought i would gain the insight and knowledge i'm missing.. and maybe direction to a source or someone tapes up an assembled bridge plate to a card, mails it, and says here - try this and either fall down or climb out.. i do it all the time here with those in my field - it's how they learn..
but either way - a new mvmt is like 100+ or nh36 150+ all parts incl... this not incl any tools i will need depending on the path chosen..
thanks for the input...
jp
 

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Craftsman
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Wow a freebie is the goal here. Welcome to the forum.

Thought my PM offer for $25 shipped ($20 + 5 USPS) for a full clean new 7S26C movement without the balance was a good deal !
OP - You would do well to take Jon up on his offer. None better on this forum than Grammarofdesign. Hell, I have gone to him for some of my parts needs and he is a reliable well respected source. Good luck on your repair or custom build or whatever you have planned.
 

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Discussion Starter · #14 ·
sorry .. was at a wake...
so i appreciate the offer.. though - i checked the exploded view - and it appears that if i understand correctly - the balance is like one of the most delicate parts in there - sitting right next to that escape wheel which is prob 2nd fragile.. or.. cannibal that mvmt and ruin it for one small section - seems like it would be a waste of a good whole piece.. when someone could make a watch from it.. i only need 2-3 parts..
and i also did not rec any mail from here.. so - not sure what happened..
as for the 'freebie'.. a part or 2 - it's nothing.. the entire mvmt - something else.. i wouldn't ask for.. not sure how your take away led you there.. but that def isn't the case.. if the mvmt was was i needed - and was clean and relatively of late model - working as it should i would certainly offer fair price.. as i said earlier - if i can locate the parts - cool.. if someone has them as extra and offers a deal of such - cool.. otherwise its off for an entire mvmt.. additionally as stated - i am trying to not change out everything at first try.. maybe 2nd try.. hence just the parts i need - if i can find them..
otherwise..
sorry you got the wrong impression.. email like text can do that..
jp
 

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I usually pull the balance first or just after the winding rotor. It’s about as fragile as any other part, however it’s certainly more exposed. That being said, the trouble shooting that you’re doing now involving the possibility of pulling off the train bridge in search of a piece of a screw or something like that which sounds to me like a much more involved intervention. Also if you even loosen the bridge plate a bit you need to be absolutely sure the train is seated before tightening down. All in all, it’s an intervention which you could mar or break something else. Oh and it’s sort of a mystery. I’d say do the donor, carefully swap the balance, then you can tear down the current one, put it back together for the experience… while wearing a running watch :)
 

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Discussion Starter · #16 ·
hello.. i appreciate the input.. sorry - it's been a long week - family wise .. seems to be crickets here - like some sort of secret clique where one has to 'pay-to-enter' - for some - i usually skip that part.
so - rant over.. .. yes, out of all the videos i've watched - it does appear that you are correct.. even saw a special 'holder' someone made for that part.. and yes - upon loosening the screws to the bridge plate - i knew i could be 'unseating' those 2 tiny little floating wheels- that i can't really see.. but it was the only means available to me to 'slide that paper under to diagnose'.. i did have to 'gently' realign or reseat those wheels to get the watch to run again before i tightened the plate screws.. see - i'm learning..
as to the 'donor'.. for the one that was 'offered - but never saw the offer' - it was missing the balance.. and someone else noted that my balance might poss be damaged - so that left me with only swapping out the plate, or the mounting 'tube' and then hoping when i put it all back that my balance was fine.. ((i think it is - as i've adjust the now running watch down to 2-3 min fast per day)) but i was also led to believe that that may not mean its running correctly at all - and could still be junk - hence the balance.. so if i were to use a 'donor' - a clean 7s26C version - i would hope it comes with a clean newer balance as well as the other pieces - at least i'll be starting higher on the 'odds are good' scale..
either way - thanks for the info... and definite reminder notes.. i've yet to locate a 'donor' - of the ones i've seen online - none are a 'c' version - trying to keep the plate of similar version year - it has the seiko name on it - also newer usually equates to cleaner and less wear.. usually.. the balance thing - well - i know not to get one from a 'b' version.. and an 'a' version it might be 'tired'.. so i'll keep searching - maybe run across a place where it's more about promoting this and less about exhibiting feathers and hierarchy..
i guess i missed the 'running' joke on the 'while wearing a running watch'... but maybe it'll catch up to me..
thanks..
jp
 

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some sort of secret clique where one has to 'pay-to-enter' ... maybe run across a place where it's more about promoting this and less about exhibiting feathers and hierarchy..
Naw man, there's no fee to entry. You're not being clear as to what you want - lots of words, very unclear. The data sheet for the 7s26c is below so we can use common terms. I'm also listing everything I think you need below because I genuinely want you to solve your issue. https://seikoserviceusa.com/uploads/datasheets/7S26C_36C.pdf

To extract a screw tail from the bridge plate so you will need a proper extractor which will cost you (100$ begeon) and you'll also have to figure out how to use it. Probably not the way to go. Alternatively, I googled for 3 min and found you this bridge plate for 10 pound, a reverse threaded screw part number 0012 539 or its also called a second reduction wheel screw for 8 pound shipped. both below.


For fun you can read about your same problem here and they come to the same conclusion, but like 8 years ago. nothing has changed. it's still a ubiquitous movement, not super rare or valuable.

or you can buy a new C version for 90$ because yours is broken and IMO you don't have the experience or training to do the repair properly- no offence, I was there too once. https://www.esslinger.com/genuine-s...ement-7s26-date-at-3-00-overall-height-7-2mm/

To be clear, this isn't a special forum where users will solve your issue for you or give you **** for free, especially when you're launching tacky quips - maybe you're trying to be funny, doesn't come off that way. I've been on this forum for mere 125 posts and I find that its a very normal place with people who do this stuff because they enjoy it. They will help you as long as you're respectful and clear with what you want.
 
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