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My treasured Seiko SKX007 finally stopped working. It didn't suffer any abuse, wasn't dropped or knocked about so I suspect the culprit to be gummy lube. The 21 jewel 7S26 movement can't be hand wound and since I didn't wear it often enough to keep it operating, it was a chore to set the day, date and time in addition to whirling it around for a couple of minutes each time I decided to wear it in my rotation. Sadly, as a result it has been on my wrist probably less than a dozen times over the last 10 years. The watch dates from the mid 1990's and I've had it serviced once about 2005 or so.

I'm in my seventies now but I have the correct tools, patience and enough remaining co-ordination to install a Seiko NH36 movement. I'm familiar with the correct procedure to effect this mod including exchanging the date wheel and cutting the new stem to properly fit the case. Rather than attempt to use the existing crown, I would purchase a new one with new seals already installed. My quandary is: do I want to do this or do I want to purchase a quartz model and leave this one as is prior to disposing of it. I doubt that it has any collectible value but I'm not an expert either. The NH35 movement can be hand wound which would be a plus but it would still be the only mechanical watch in my modest collection of less than a dozen watches. 

Having the 7S26 movement serviced is fiscally unappealing. Service costs are now as much or more than I paid for the watch originally. With the NH36 movement, this would be a bridge to cross in the future so perhaps I would only be delaying the inevitable. I'm not asking for a show of hands here, just some input on whether or not to leave an original watch alone.

Ta,

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I would want to know why you describe it as "treasured"? If it has sentimental value and you would just like it to work, regardless of what's inside, then I say replace the movement. Could be a fun project.

Otherwise, if you think you're likely to get rid of it, I would leave it alone. Virtually every collector I know values originality over all else, and even if they don't, leaving them the choice to make changes is always the better move.

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I'd service the seiko movement, keeps it original spares are plentiful, if you have the stuff about you to change a movement and cut stems fit hands etc etc you should be able to service that movement. Don't swap it out for a quartz that would be a sacrilidge 

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Actually, I've decided to keep the watch as original as possible. I now own a watch with a Seiko NH36a movement and while I like it, I don't care for it enough to duplicate it in my Seiko XKS007. Besides, who doesn't enjoy a little variety? I removed the case back and used the proper screwdriver to wind the barrel manually. Nothing changed other than I didn't feel much, if any tension as I wound it up. 

I used a piece of new pegwood to hold open the click spring while simultaneously holding the barrel screw to let off the tension and begin anew. It turned out that there was no tension on the mainspring at all. I have no idea whether it's a broken mainspring or if it has another issue but clearly the reason for the watch's failure to run is a lack of motive power.

I've sourced a brand new, 7S26 Seiko movement assembled in Malaysia from a trusted wholesale supplier here in the US. Yes, I could save a few $'s by purchasing one on fleabay that comes from Singapore but I would rather support my favorite parts house and with Esslinger, I know that I'll receive a quality item. I'm not knowledgeable enough to know whether a movement from an unknown source is genuine or not. 

My plan is simple. I'm going to switch out the movements, then disassemble the faulty unit while I enjoy wearing my watch again. Should I muck up the old movement, I'm no worse off and there's plenty of help on this forum if needed. Wish me luck....

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Well done mate, glad you’ve chosen to not put a quartz in, have fun swapping out the movements. You seem to know what you are doing so I can’t see you having any snags, as for help you’ll get loads the venerable Seiko movement is very popular and spares are plentiful ok

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I should have noted that I'm going to replace my 7S26a movement with a 7S26c version. The major differences that I can see are the balance cock and the method of regulating the movement. I'll be rebuilding the 7S26a for a spare. I've already noted that Seiko recommends replacing the barrel and mainspring as a unit. Naturally, it's a discontinued part. I won't know if I can repair mine until I remove it and take a peek.

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I'm interested in this also as have a couple of watches with 4R36 movements.  These are hacking and winding movement variations of the same theme and are cheap on ePay usually as NH36 or 36A.  The A denotes day and date.  There are several Youtube vids on swapping these in place of the 7S26.  Worth the effort IMHO.

I just learned that the 3:00 stem movements will work in the Seiko divers with 4:00 setting, but you must change the day dial and cut a new stem.  It seems to be a commonly done "Mod".

 

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An update on my project. I'm still mentally flexible enough to alter course when a new path seems more appealing. I've opted to purchase a new 7S36C movement from an individual on another forum. This is the upgraded version of the original 7S26a that came in the watch. The owner of the movement swapped it out of a new Seiko for the 7S36a which has hacking and stem winding complications. Additionally, since the movement was sold originally in Europe, it was actually manufactured and assembled in Japan. Whether or not that's actually a benefit is open to speculation. 

I have to admit being a bit pleased with my decision to basically retain the original features of the watch. The new movement will not have hacking or stem winding capabilities but that's fine with me. It will have the new balance staff and regulation system plus the addition of two additional jewels. I'm also going to change the hands for something quite different (easier to see with my 72 year old eyes) and I've sourced a new jubilee style aftermarket bracelet that is a significant upgrade from the original. Besides, after 22 years of use, the previous bracelet was a bit loose in all the fittings. 

Once the project has been completed, I will be happy to post a full summary along with pictures. In the meantime, I'm awaiting delivery of items from Boston, Germany and Australia for this project. It may take a bit of time but the end result will hopefully be very satisfying. 

Edited by TexasDon
clarity, spelling

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This project is slooooowly moving forward. Actually, it's sort of like a dance. Two steps forward, one step back. My source for the Seiko 7S36 movement forgot to ship it prior to leaving on an extended business trip but, he did remember to pack it along. So, he shipped it from The Philippines instead of his home in Burbank, CA. Then, he sent it signature required, which was fine. However, he neglected to inform me of that , which wasn't so fine. As a result, I was away when the movement arrived on Saturday and missed it. I drove to the post office this morning and retrieved it. 

I could attach a photo if anyone wants to see yet another Seiko automatic movement. This one is different only in its point of manufacture. My counterweight says made in Japan and 23 jewels, instead of 21. Other than that, it's identical to the current 7S26C movement. 

This movement has the black day and date dials and I'm thinking of leaving them. Rather stupidly, I assumed that everything inside the case was correct when I removed all the parts so I failed to properly examine all components. I discovered this morning that one of the dial feet is missing. This particular watch began life in The Philippines as a working tool on the arm of a diver. Prior to my purchasing it, the selling dealer completely rebuilt the movement, polished the case, installed a new hardlex crystal etc. I'm fairly certain that I didn't break off the mounting foot but I do recall some slight amazement at how easy it was to remove at the time. Either way, no use crying about it now. I've ordered a new dial as I see absolutely no reason to reinstall a faulty one.

I've checked high and low and the missing foot is nowhere to be found, including still stuck in the movement holder. I don't believe it was ever there. As I'm still awaiting a new set of hands that were shipped from Australia early in January, the missing dial foot doesn't represent an issue other than buying a replacement dial. Once the hands and the new dial arrive, I can finally begin reassembling the watch. I think the black day/date rings are going to look great. The new crown that I purchased fit the stem perfectly. This crown has an inner O-ring in the base of the crown so it will add an additional layer of watertight integrity. Us old submarine sailors tend to place a premium on that item.

Anyhow, that's the way things stand as of now. More when additional parts arrive.

Edited by TexasDon
spelling

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Finally, the parts have just about dribbled in. I'm awaiting only the replacement dial and it's on US soil, inbound to me from the port of Los Angeles. It might reach me by Friday. So far, the case has been stripped, cleaned and polished. I've replaced the stock bezel with an aftermarket coin edge stainless steel model. After installing a new bezel gasket and a green insert, it snapped into place easily with a press. 

Next, I replaced the original flat mineral glass with a double domed, blue AR coated sapphire version. I have the replacement movement (Seiko 7S36, 23J) ready to go with the exception of installing the hands. They finally arrived from Australia after being in transit 39 days. I'll show them after the new dial is fitted.

Seiko-mod.jpg

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Typical of a submarine sailor !People think you guys are crazy , but what they don't understand is that if you don't do everything exactly right everyone aboard ship dies from radiation poisoning. Bravo brother ! YD

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The project finally came to fruition today. The new dial arrived and I assembled the old girl. At first, I couldn't get the movement to align with the chapter ring properly. After further investigation, I found that I had somehow let the chapter ring slip when installing the new crystal. Out came the crystal again, correctly aligned the chapter ring with the keeper in the milled slot, then reassembled it all. Now, everything's good to go. 

Old: 7S26 21J mechanical auto wind movement, flat mineral glass crystal, factory supplied hands. Literally, any stock SKX007 will show you what I began with.

New: 7S36 23J mechanical auto wind movement, double domed blue AG coated crystal, custom coin edge 316L bezel, green insert, new crown.

I've installed the original Jubilee bracelet from Seiko that the watch has always worn. I've ordered new fat spring bars as the old ones are a bit dodgy. I won't wear the watch until I have those in hand and change them out. Total cost of parts = $92. Labor = $0. Fun involved with project = priceless! A big old Texas "Thank you pardner" goes out to Mark without whose videos and encouragement this would have never happened. 

SKX1_50.jpg

SKX2_50.jpg

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