Seiko 7S26 Movement Details
Seiko caliber 7S26 is an automatic watch movement produced from around 1996.
Search eBay for watches with this movement.
Sub-brands: | Seiko 5, S-Wave |
Power reserve: | 41 hours |
Accuracy: | +35/-25 seconds/day |
Day / date? | Day + date |
GMT / world time? | No |
Chronograph? | No |
Hacking? | No |
Rate: | 21,600 bph |
Number of jewels: | 21 |
Lift angle: | 53º |
Size / diameter: | 27.0mm |
Height: | 4.9mm |
Stem code: | 351260 (tap 10), 351261 (tap 10) |
Balance wheel code: | 310020, 310197 |
Mainspring code: | 201024, 201075, 201083 |
Notes: | The same as cal. 7S25 but with day display (as well as date). The difference between 7S26A and 7S26B is an upgrade to an Echtacron-style regulator for easier adjustment. Changes in 7S26C are the addition of a lower arbor jewel and making all four date dial guard screws identical – no more frustratingly small cross-head screw! |
PDF guides: |
Technical guide for 7S26A & 7S36A
Technical guide for 7S26B & 7S36B Technical guide for 7S26C & 7S36C |
Related movements: | 7S25 7S35 7S36 7S55 |




Articles
- SKX Pilot (a thirty minute mod) [adventuresinamateurwatchfettling.com]
- An intermission: Notes on the 7S26 autowinder efficiency [adventuresinamateurwatchfettling.com]
- Variations on a theme [adventuresinamateurwatchfettling.com]
- Service: Seiko 7S26-0200 Scuba Diver’s watch [watchguy.co.uk]
- Restoring a Seiko 5 Sports [tentotwo.nl]
- Seiko SKX007 [thewatchbloke.co.uk]
- Seiko Black Bay mod [thewatchbloke.co.uk]
- Seiko 7S26A [17jewels.info]
- Seiko 7S26 caliber - The father of 7S family of movements [strapcode.com]
- Seiko NH36 Walkthrough [watchrepairtalk.com]
- Seiko 7S26A Complete Service Walkthrough [watchrepairtalk.com]
- Seiko 7S26-02JO Service [mitka.co.uk]