Seiko 7S26 / NH26 Parts

The NH26 (old NH23) and the 7S26 movements are quite similar because they are both simple, reliable automatic movements produced by Seiko Instruments Inc. (SII). However, the NH23 is a more modern version designed for external manufacturers (e.g., microbrands), while the 7S26 was exclusively used in Seiko watches. Here are the key differences and similarities:

Similarities

1. Mechanical Base:

   • Both are automatic movements without manual winding or hacking features.
   • They share similar specifications:
     • Beats per hour (BPH): 21,600.
     • Power reserve: Approximately 40 hours.
     • Number of jewels: 21.

2. Use Case:

   • Both are designed for entry-level, affordable watches.
   • Renowned for their simplicity, reliability, and low maintenance.

3. Day and Date Complication:

   • Both movements feature a day-date function, often with the day displayed in two languages (depending on the watch).

Differences

Advantages of the NH26 Over the 7S26

1. Availability:

   • The NH26 is still in production and readily available from aftermarket and wholesale channels.
   • The 7S26 has been discontinued, making it harder to source complete movements or spare parts.

2. Flexibility:

   • The NH26 is widely used by microbrands and external manufacturers, offering greater versatility.
   • The 7S26 was limited to Seiko watches, making it less adaptable for aftermarket use.

3. Modernized Production:

   • While functionally similar, the NH26 benefits from more modern production techniques, potentially offering improved consistency and reliability.

When to Choose Which?

• NH26:

  • Best for new watches, microbrand projects, or aftermarket replacements.
  • Ideal when you need a modern, widely available movement.

• 7S26:

  • Only relevant for repairing Seiko watches or vintage projects where using an original Seiko movement is essential.

Conclusion

The NH26 is essentially a modern, aftermarket-oriented version of the 7S26. The primary difference lies in availability and target audience: the NH26 is versatile and designed for broader applications, while the 7S26 is a classic Seiko movement that was exclusive to Seiko watches.