Seiko Caliber 7s26a Movement

Seiko Caliber 7S26

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Seiko Caliber 7s26a Movement

Manufacturer Seiko
Caliber Number 7S26
Movement Type Automatic
Diameter
27.4mm
Casing Diameter
27mm
Height
4.8mm thick
Jewels 21
Vibrations Per Hour
21,600 bph
Shock System Seiko Diashock
Regulator
Etachron
Lift Angle
53 degrees
Power Reserve
~41 hours
Magnetic Resistance 4,800 A/m (60 gauss)
Winding Direction
Bi-directional (Magic Lever)
Hand-Windable? No
Hacking? No
Functions Hours, minutes, central seconds, day/date calendar at 3:00
Country of Manufacture Japan/Malaysia/Singapore
Known Brands
Seiko Scuba Diver’s (add more in the comments below)

The Seiko caliber 7S26 is an automatic movement used in many popular Seiko divers and the entry level Seiko 5 watches. This movement was first released to the market in 1996. The most recent tech sheets found were dated 2011.

Discontinued

Modern Seiko watches, such as the Next Gen Orange Monster, have since been upgraded to the caliber 4R36, making Seiko collectors happy because the 7S26 seen here does not hack and is not hand-windable – two functions that have become more and more popular.

7S26A VS 7S26B VS 7S26C

The letter indicates the evolution of the caliber 7S26. 7S26 and 7S26A is the first generation of this caliber and are the same. 7S26B is the second generation. 7S26C is the third and final version.

The difference between A/B in Seiko’s own words:

“Cal. 7S watches are changed from caliber “A” to caliber “B” in October 2006 production. According to the change, we would like you to pay attention to the design of the balance staff when repairing those watches.” -Source: Seiko Parts Catalogue/Technical Guide Cal. 7S26B, 7S36B. Published 2007.

The difference between B/C in Seiko’s own words:

“SEIKO Automatic Mechanical Cal. 7S26C / 7S36C are replacement caliber of Cal. 7S26B / 7S36B. Construction of the C series is same as B series, but using new parts. Since the size of movement is same as B series, the complete movement can be assembled into the watches which originally have the B series move-ment; however, as the parts are not convertible, please use the appropriate parts for each caliber.” -Source: Seiko Parts List/Technical Guide Cal. 7S26C, 7S36C. Published 20011.

7S26 VS 7S36

The main difference between the 7S26 and the 7S36 is that the caliber 7S36 has 2 extra jewels. The 7S26 has 21 jewels and the 7S36 has 23 jewels. Many enthusiasts refer to this as 2 non working jewels. There is speculation that the 7S36 was supposed to eventually replace the 7S26, but that never actually happened.

WUS user Biased&Critical explains the comparison in detail:

The extra 2 jewels are on the “lower bridge for 3rd wheel and pinion”. They are lower cap jewels for the 3rd and escape wheels. But that’s a bit of a fancy answer – here’s an easy one: they are basically useless jewels and do nothing to alter performance… To answer your question, as far as complete swapouts go, they are interchangeable. But that would be a practice in futility – you wouldn’t gain or lose anything but (your own) time. I have both of these movements, have for years, and there is no practical difference. But to repair, there are some things to consider. Some of the parts are different in size – you can find the details around here somewhere, but the 3rd and escape wheels have different axle lengths due to the jeweled capping. Not to mention this bridge that simply does not exist in the 7s26. Maybe something else equally minor.

7S26C/7236C Part Differences:

  • Screw for lower bridge for 3rd wheel and pinion
  • Lower bridge for 3rd wheel and pinion
  • Oscillating weight

Seiko Caliber 7S26A Gallery:

Seiko Caliber 7s26a Etachron Regulator Seiko Caliber 7s26a Macro Gears

Example of a Seiko caliber 7S26C:

Seiko caliber 7S26C made in Malaysia

Seiko Caliber 7s26c Calvinwcyy

Seiko Caliber 7s26c Calvinwcyy 1

Additional Resources:

Is the Seiko Caliber 7S26 any good? Share your opinions, experiences and watches below... Remember to keep comments respectful and follow our community guidelines.

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[…] calibers: while both are Japan automatic movements, the Seiko is using a 7S26 while the Spinnaker has an […]

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[…] SKX175 employs Seiko’s widely-used 7S26 automatic movement. While it might not be the most accurate design available, it has a reputation as a solid workhorse […]

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[…] you might be able to read the tiny text at the bottom of the dial stating that the SNKK71 uses Seiko’s 7S26 automatic movement. With 21 jewels to damped vibration, this movement is renowned for its reliability and accuracy at […]

Carlos Velazquez
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Carlos Velazquez

I need parts or the movement for Seiko 7S26
Thanks

Carlos Velazquez
Guest
Carlos Velazquez

Thank you for the information
Carlos

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[…] 7S26 […]

Marco
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Marco

Seiko Military/Pilot Style Watches SNK80x series

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[…] Seiko caliber 7S26: calibercorner.com… […]

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[…] First things first. This is an automatic watch. Technically, it is Seiko’s 7S26 automatic movement. […]

Fred
Guest
Fred

Very good caliber, reliable and good accuracy and the shock system is very good. Mine felt from 1.5m on hard floor and no problems, really good and cheap workhorse caliber 7S26.

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[…] You might also want to consider the NH35. Further reading:Seiko Caliber 7S26 Watch Movement | CaliberCorner.com And it is also said, "go not to the Elves for counsel, for they will say no and yes." — […]

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[…] your frequent usage of the watch as it comes with a 40 hour battery reserve. The good side is that 7s26 is a decent automatic movement, beating at 21600 BHP and featuring 21 […]

Alan
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Alan

Do you still need pictures of this calibre?

Ntseh Lovet
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Ntseh Lovet

I have owned a Seiko 7S26A since 2007. It has sustained fall shocks and minor scratches but yet still works, albeit with constant time adjustments. I think it needs to be refurbished.

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[…] exactly what Seiko is all about. This superb Seiko 5 timepiece comes with 21 jewels and uses a 7S26 caliber self-winding mechanical movement that cannot be manually […]

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[…] I have harped on about a number of times, one of the most notable features of this range is the 7S26 Automatic movement with 40 hrs power reserve. It is quite a basic movement for Seiko, but let’s face it – […]

Jorge Lara Gonzalez
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Jorge Lara Gonzalez

Tengo un seiko automatico 7s26c, necesito saber si es sumergible y a cuantos metros.

nizam
Guest
nizam

How much Dh ?

Carrie
Guest
Carrie

What is Dh?

Septian Blog
Guest

This caliber overall is so good, i have nice experience with seiko 5 SNK805.

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[…] Calibrul 7S26 : e un mecanism lansat in 1996 si pe care Seiko l-a folosit de-a lungul timpului pe mai multe modele, este automatic cu 21 de rubine, autonomie 40 ore (minim), nu se poate intoarce manual, este recunoscut pentru fiabilitatea sa. […]

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[…] of those areas. Sure, it’s reliable and works well, but it just does what it needs to. It is the 7S26 movement with a day and date display, which if you think about it is also something that typically adds more […]

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[…] Seiko Caliber 7S26 Watch Movement | CaliberCorner.com Is it e-bay from India? It should be special! Reply With Quote […]

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[…] hablemos del elefante en la habitación. El 7s26 ha sido elogiado y repudiado simultáneamente en todos los foros de la comunidad relojera en la […]

Calvin
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Calvin

Hi, i have very high quality photos of the movement for my Seiko 5. Would you like to have it?

Paulo Balsan
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Paulo Balsan

Where can I find this caliber’s accuracy in seconds?

Buck
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Buck

Also known as cal V676. 🙂

Carrie
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Carrie

In what watch? Never heard of V676 before. Are you sure this is correct?

Buck
Guest
Buck

Yes, I’m sure, it’s fitted to various Seiko sub-brands such as Alba.

Buck
Guest
Buck

Apologies for the typo Y676!!

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[…] turn this metallic watch over to view its constantly cranking automatic watch movement. The Seiko Caliber 7S26, which is written in fine print on the face of the watch, is a refined yet simple watch movement […]

Dave
Guest
Dave

Excellent movement for the basic Seiko 5 (excellent watches by the way, inexpensive but not ‘cheap’). However, the Orange Monster does need the NH35 movement, the 7S26 being too modest. Heck, I’ve got an Invicta Pro Diver (a great watch by the way, don’t be misled by watch snobs) with the NH35 movement!

Tim
Guest

What a beautiful Seiko! Do you know if they’re selling it in the US? I haven’t seen it around?

Toussaint
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Toussaint

Yes, you can find it on Amazon for $90.