Seiko 2623A – Technical Guide (High Quality)

The Seiko 2623A is a compact and efficient quartz analog movement developed in the late 1970s to early 1980s. As part of Seiko’s 26xx quartz movement family, the 2623A features three-hand functionality (hour, minute, and central seconds), offering a complete time display in a slim, small-diameter format designed primarily for ladies’ wristwatches. The addition of a sweep seconds hand distinguishes it from many other compact calibers of its era, which typically excluded that function to save energy and space.

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1. Technical Specifications

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2. Key Features

• Three-hand display in an ultra-compact quartz module

• Slim profile, suitable for ladies’ and small-size watches

• Hacking seconds allows for precise time setting

• No date complication, simplifying the design and extending battery life

• Highly efficient quartz IC and step motor

• Robust step motor design enables steady second-hand movement every 1 second

• Designed for ease of service and long-term reliability

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3. Movement Layout

Components:

• Quartz oscillator (crystal) at 32,768 Hz

• Integrated Circuit (IC) to divide frequency and control impulses

• Step motor and rotor to drive the gear train

• Gear train to transfer energy to hour, minute, and second hands

• Time-setting mechanism: crown, clutch wheel, and sliding pinion

• No calendar or date wheel, allowing for simplified construction

The 2623A is modular, making battery replacement and gear inspection straightforward.

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4. Battery Information

Battery Replacement:

1. Open the case back using a case opener (snap-on or screw-back).

2. Remove the battery using plastic tweezers.

3. Clean contact points if corroded.

4. Insert new battery with correct polarity.

5. Reset the time and check for movement.

⚠️ Avoid touching the quartz crystal or coil. Use ESD-safe tools.

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5. Common Issues & Solutions

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6. Watch Models Featuring the 2623A

The Seiko 2623A was used in a wide range of ladies’ watches designed for markets in Japan, Europe, and North America between 1979–1985. These models generally included:

• Simple dress watches with small case diameters (~18–25 mm)

• Minimalist dials with no date window

• Slim cases, often stainless steel or gold-tone

• Acrylic or mineral glass crystals

• Case references such as:

  • 2623-0030

  • 2623-7000

  • 2623-5010

These watches were praised for their refined style, accuracy, and lightweight comfort.

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7. Servicing Tips

• Do not lubricate plastic gears unless explicitly noted

• Clean under magnification; small movements are sensitive to fiber or dust

• Inspect and clean the coil and rotor teeth for corrosion or magnetic particles

• Replace stem gasket and case gasket to retain water resistance after opening

• Always use an anti-static mat and wrist strap when handling the movement

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8. Conclusion

The Seiko 2623A is a highly efficient, compact quartz movement that offers complete three-hand timekeeping in a slim and service-friendly package. With its hacking seconds, excellent power efficiency, and simple architecture, it continues to serve as a reliable heart in many vintage Seiko ladies' watches.

Whether for collectors, repair specialists, or vintage wearers, the 2623A remains a dependable and practical choice for everyday precision and understated elegance.

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