Seiko 2625B – Technical Guide (High Quality)

The Seiko 2625B is a refined version of the 2625A quartz movement, part of Seiko’s trusted 26xx series developed in the early 1980s for ladies’ watches. Like its predecessor, the 2625B is a three-hand analog movement with a date complication, designed for compact cases where space efficiency, low power consumption, and precise timekeeping are essential. With small upgrades in electronic layout and mechanical tolerances, the 2625B offers even greater reliability for elegant timepieces.

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1. Technical Specifications

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2. Key Features

• 3-hand display: Hour, minute, and sweep seconds

• Date window at 3 o'clock with quickset functionality

• Hacking seconds for precise time adjustment

• Ultra-compact quartz architecture, perfect for slim ladies’ watches

• No day function, keeping the design clean and efficient

• Improved coil durability and circuit insulation compared to 2625A

• High serviceability and low power usage

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3. Calendar Operation

Setting the Time and Date:

• Crown Position 0: Normal running

• Crown Position 1 (1st click):

  • Turn clockwise to quickset the date

• Crown Position 2 (2nd click):

  • Set time (hacking function engages – second hand stops)

⚠️ Avoid using quickset between 9:00 PM and 2:00 AM as the calendar mechanism may be in engagement and could be damaged.

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4. Movement Architecture

Core Components:

• Quartz oscillator (32.768 kHz)

• Integrated circuit (IC) with step motor control

• Step motor & rotor gear to power the hands

• Cannon pinion and center wheel for smooth timekeeping

• Date mechanism: Date ring, jumper spring, quickset gear

• Setting assembly: Crown, clutch wheel, and sliding pinion

2625B Improvements over 2625A:

• Refined IC circuitry for better temperature stability

• Improved electrical contact design

• Slightly more efficient gear tolerance for smoother seconds hand sweep

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5. Battery Replacement

Procedure:

1. Open the case back carefully using proper tools

2. Remove old battery with plastic tweezers

3. Clean contact points if corroded

4. Insert new battery (positive side facing up)

5. Confirm hand motion within 10–15 seconds

6. Set time and date, reseal case (replace gasket if needed)

⚠️ Always use ESD-safe tools and take precautions to avoid static discharge.

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6. Troubleshooting & Repairs

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7. Watch Applications

The 2625B was commonly installed in Seiko ladies’ watches in the early to mid-1980s, including:

• Classic dress models with small round or oval cases

• Date window cleanly positioned at 3 o’clock

• No day display, maintaining dial symmetry

• Stainless steel, two-tone, or gold-tone cases

• Domed acrylic or flat mineral crystals

• Case references like:

  • 2625-0030

  • 2625-7000

  • 2625-0010

These watches were marketed globally as slim, elegant, and dependable quartz timepieces for everyday use.

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8. Service Tips

• Clean gear train and date jumper using pegwood and soft brush

• Avoid over-lubricating any metal-to-metal surfaces

• Always replace the case gasket after battery replacement

• Check hand clearance after reassembly—hands may foul in thin cases

• Use watch paper under the dial during work to prevent scratches

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9. Conclusion

The Seiko 2625B is a well-balanced quartz movement that delivers three-hand accuracy and quickset date functionality in a durable and space-saving format. Its reliability and ease of maintenance made it a workhorse in Seiko’s vintage ladies’ lineup. Today, it remains a collectible and restorable movement—proof of Seiko’s quartz excellence during the golden era of analog watches. With routine servicing and proper care, the 2625B can continue ticking for decades to come.

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