Introduction to the Seiko 6M25A

The Seiko 6M25A is a Kinetic Perpetual Quartz movement with integrated daily alarm, developed in the early 2000s as a refinement of Seiko’s advanced 6M-series calibers. Like its siblings (6M13A, 6M15A, and 6M23A), the 6M25A combines Seiko’s Kinetic energy system with analog quartz accuracy and the Auto Relay sleep function, but it uniquely includes an analog alarm complication—a rarity in perpetual calendar watches.

This movement was typically installed in premium Seiko models such as the Premier and select Brightz releases, designed for wearers who wanted long-term precision, power autonomy, and functional versatility.

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Technical Specifications

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Key Features

• Kinetic energy system: Charges the internal capacitor via wrist movement

• Perpetual calendar: Automatically adjusts for varying month lengths and leap years through 2100

• Auto Relay sleep mode: Hands stop after 24 hours of no movement to conserve energy

• Alarm function: Daily, analog alarm activated at set time via independent hand

• Dual stepper motors: One for time/calendar and one for alarm control

• Long-term memory: Circuit continues to keep time internally, even in sleep mode

• Elegant analog layout: Seamlessly integrates calendar and alarm functions into a refined dial design

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Power Management

Charging

The rotor spins while worn, generating current stored in the capacitor. Watches in frequent use rarely run low on power.

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Sleep Mode (Auto Relay)

• Activates after 24 hours of no movement

• Hands stop moving, but internal circuit continues timekeeping

• When movement is detected again, the hands automatically reset to the correct time

• Perpetual calendar continues tracking even in sleep mode

• Power reserve in this state lasts up to 4 years

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Setting Instructions

Crown Positions

• Turn clockwise in Position 1: Adjusts date

• Turn counterclockwise in Position 1: Adjusts month/leap year

• Pull to Position 2: Set the time; second hand stops for precise alignment

Alarm Setting

• Controlled via separate crown or recessed pusher, depending on model

• Set by rotating or clicking to move alarm hand to desired time

• Alarm hand typically located on a subdial, often at 6 o’clock

• Alarm sounds for ~10–15 seconds when current time matches alarm hand

Some models include an alarm on/off indicator or a visual cue on the dial.

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Capacitor and Replacement

• Capacitor Model: Panasonic MT920 or equivalent

• Voltage: 1.5V

• Service Life: 8–10 years under normal use

Replacement Steps

1. Open case back carefully

2. Remove the old capacitor with non-metallic tweezers

3. Insert the new capacitor and secure it

4. No reset (AC) required — movement reactivates automatically

5. Fully charge by wearing or using Seiko’s charger

6. Reset time, calendar, and alarm after power is restored

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Maintenance and Servicing

The 6M25A is modular and durable, but not user-serviceable. It requires specialized tools and skill.

Service Checklist

• Capacitor check/replacement every 8–10 years

• Calendar geartrain inspection (for sticky transitions)

• Alarm buzzer cleaning if sound is weak

• Regulation (via trimmer capacitor, if accessible)

• Confirm Auto Relay and hand alignment after charging

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Troubleshooting Guide

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Watches Featuring the 6M25A

You’ll find the 6M25A in:

• Seiko Premier Kinetic Perpetual Alarm watches

• Select Brightz JDM models featuring alarm complication

• High-end dress watches with polished stainless cases, sapphire crystals, and multi-layered dials

• Models labeled “Kinetic Perpetual” and “Alarm”

These timepieces were designed for professionals who desired precision, convenience, and daily-use practicality.

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Conclusion

The Seiko 6M25A is a rare and versatile movement offering:

• Kinetic power generation

• Perpetual calendar through 2100

• Daily analog alarm

• Auto Relay sleep function for long power retention

• Elegant design and durable components

For those who want functionality without compromise, the 6M25A delivers mechanical autonomy, quartz precision, and luxury-grade engineering—making it one of Seiko’s most complete and refined hybrid calibers.

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