Seiko 395 – Technical Guide

The Seiko 395 is a compact, two-hand quartz movement designed for use in small, elegant wristwatches, especially in women’s fashion and dress watches. Similar in construction and purpose to the Seiko 394, the 395 offers reliable timekeeping, long battery life, and a minimal design that makes it ideal for ultra-thin watch cases.

This guide provides a detailed overview of the Seiko 395’s specifications, internal components, battery servicing steps, and common troubleshooting.

Movement Overview

The Seiko 395 is a two-hand analog quartz movement, displaying hours and minutes only. It does not include a seconds hand or date complication, helping to keep energy usage low and the movement thickness minimal.

Technical Specifications:

• Caliber Number: 395

• Movement Type: Quartz

• Functions: Hour and Minute

• Size: 5 ½ × 6 ¾ lignes (approx. 13.0 mm × 15.15 mm)

• Height: ~2.00 mm

• Battery Type: SR516SW (317)

• Battery Life: Approx. 3 years

• Accuracy: ±15 seconds per month

• Jewels: None (uses metal or synthetic bushings)

This movement is commonly used in vintage and mid-range fashion watches that prioritize a slim and discreet profile.

Key Components and Internal Layout

The Seiko 395 shares many architectural similarities with other Seiko micro-quartz movements. Its construction emphasizes compactness and ease of service:

• Quartz Oscillator (32,768 Hz): Ensures consistent and accurate timekeeping.

• Integrated Circuit (IC): Governs timing pulses sent to the step motor.

• Step Motor & Coil Block: Converts electrical pulses into mechanical motion.

• Gear Train: Drives the hour and minute hands through smooth rotation.

• Battery Clamp & Insulator Plate: Holds the battery in place and ensures safe, uninterrupted power flow.

Because of its minimal functions, the 395 is a low-maintenance, highly efficient timekeeping module.

Battery Replacement Instructions

Battery servicing is simple but should be carried out with precision to avoid damaging miniature components.

Battery Replacement Steps:

1. Open the Case Back: Use the proper tool (case knife or fine case wrench).

2. Remove the Old Battery: Use non-magnetic plastic tweezers to remove the SR516SW cell.

3. Inspect Contacts: Clean gently with pegwood if any debris or corrosion is present.

4. Insert New Battery: Place the new SR516SW with correct polarity.

5. Test the Movement: Observe hand movement within 5–10 seconds.

6. Reassemble Case: Ensure gasket alignment if the watch is water-resistant.

⚠️ Tip: Always use anti-static tools or gloves when handling the movement to avoid ESD damage.

Common Issues and Troubleshooting

Though reliable, some issues may occur with aging or mishandling:

Because of its micro size and low production cost, the movement is typically replaced entirely if damaged.

Conclusion

The Seiko 395 is a highly efficient, ultra-compact quartz movement made for refined and slim timepieces. Its simplicity, long battery life, and minimal servicing needs make it ideal for watches that prioritize style and low profile over complexity.

Whether you're a collector maintaining vintage Seiko models or a technician performing routine service, the 395 remains a dependable and easy-to-handle caliber that showcases Seiko's enduring commitment to elegant, precise timekeeping.