Seiko 5H22A Technical Guide

Introduction

The Seiko 5H22A is a quartz analog movement with a full day-date complication, developed during the late 1980s and widely used through the 1990s. It was a cornerstone in Seiko’s mid-tier quartz lineup, built for reliability, accuracy, and ease of use. The 5H22A offered practical functionality like quickset day and date, hacking seconds, and a robust architecture suitable for everyday wear watches.

This caliber served as a bridge between Seiko’s earlier quartz designs (like the 7C series) and more modern iterations, and it remains well-regarded for its long lifespan, intuitive design, and serviceability.

Technical Specifications

• Caliber: Seiko 5H22A

• Movement Type: Quartz analog

• Functions: Hour, minute, central seconds, day, date

• Jewels: 2

• Accuracy: ±15 seconds per month

• Battery Type: SR920SW (1.5V silver oxide)

• Battery Life: ~3 years

• Hacking Seconds: Yes

• Quickset Day/Date: Yes

• Manual Reset (Zero Positioning): Yes

• Calendar Languages: Typically English + Spanish or Kanji

• Movement Diameter: ~23.5 mm

• Height: ~2.9 mm

• Integrated Circuit: CMOS-based quartz oscillator

• Temperature Compensation: No

Key Features

Full Calendar with Quickset

The 5H22A includes both day and date displays, located most often at the 3 o'clock position. Adjustment is fast and easy:

• Quickset Date: Pull the crown to the first position and rotate clockwise.

• Quickset Day: Rotate crown counterclockwise.

This mechanism is user-friendly and durable but should not be adjusted between 9 PM and 3 AM, when the automatic date change is engaged.

Hacking Function

The hacking feature (also called stop-seconds) allows the seconds hand to stop completely when the crown is pulled out to the second position. This enables precise synchronization with a reference time source—a must-have feature for many watch enthusiasts.

Manual Reset (Zero Positioning)

After a battery change or impact, hand alignment can be corrected using the manual reset feature. This is done by shorting the AC (All Clear) terminal to the battery with a conductive tool, allowing the movement to realign all hands to their correct positions.

Durability and Performance

The 5H22A was engineered for robustness. While it only contains 2 jewels, these are placed at high-friction pivot points to extend movement life. The architecture is clean and modular, making it accessible for servicing or replacement.

This movement was designed with longevity in mind. Many watches using the 5H22A continue to run accurately after 20–30 years, with only battery replacements and occasional servicing.

Watches Featuring the 5H22A

The 5H22A was used in a broad range of Seiko quartz watches from the late 1980s to early 2000s, including:

• Seiko Quartz Day-Date models

• Seiko 5 Quartz line (not to be confused with automatic Seiko 5s)

• Stainless steel dress and field-style watches

• Gold-tone two-hand formal watches with slim cases

Dial designs ranged from classic Roman numerals and stick indices to field-style military numerals.

Servicing and Parts

Battery Replacement

• Use only SR920SW (1.5V silver oxide).

• Always inspect for corrosion, especially on vintage units.

• Reset the movement after installation using the AC contact.

Maintenance Tips

• Avoid adjusting calendar functions during automatic changeover period.

• Gently clean the PCB and contact points with non-corrosive solutions.

• Avoid magnetic tools and static discharge near the IC.

Parts Availability

While discontinued, the 5H22A is still supported by a strong secondary market. Donor movements are often used for wheels, coils, date disks, and hands. The case dimensions and stem length are also compatible with other Seiko calibers from the same period.

Summary Table

Conclusion

The Seiko 5H22A is a resilient and well-engineered quartz movement, emblematic of Seiko’s attention to usability and durability. Its straightforward design, solid timekeeping, and dependable calendar features make it an excellent movement for collectors restoring vintage quartz pieces or seeking an everyday reliable watch. Though quietly sitting beneath Seiko’s more famous calibers, the 5H22A has more than earned its place in quartz horology history.