The Seiko A354A is a vintage digital quartz LCD movement introduced in the early 1980s and best known for powering some of Seiko’s multi-alarm digital watches. This caliber marked a step forward in functionality within Seiko’s A-series by offering multiple alarms, in addition to core features like timekeeping, calendar, stopwatch, and 12/24-hour display formats. The A354A served as the base module for several robust and well-loved Seiko digital watches, particularly those aimed at professionals and sports users.

Technical Specifications

• Caliber Number: A354A

• Movement Type: Quartz (Digital LCD)

• Display Type: Liquid Crystal Display, 7-segment format

• Primary Functions:

  • 12-hour or 24-hour Timekeeping

  • Day and Date Calendar

  • Multiple Daily Alarms (usually 3)

  • Stopwatch (1/10-second resolution)

• Backlight: Not integrated (some watches had external case-mounted light modules)

• Battery Type: SR1120W (1.55V silver oxide)

• Battery Life: Approximately 2 years

• Accuracy: ±15 seconds per month

• Module Dimensions:

  • Width: ~26 mm

  • Height: ~22 mm

  • Thickness: ~5 mm

Display Layout

The A354A module features a logical and clean LCD layout, typically including:

• Top Line:

  • Day of the week (MO, TU, etc.)

  • Function indicators such as “AL1,” “AL2,” “AL3” (for individual alarms), “ST” (stopwatch), “PM,” or “24H”

• Main Display Area:

  • HH:MM:SS format for time

  • Calendar mode shows date in MM-DD or DD-MM depending on regional settings

  • Stopwatch readings in MM:SS.t format (tenths of a second)

The design prioritizes clarity and ease of use, even in low-light conditions (on models with external lighting).

Operating Modes

1. Time Mode

• Shows current time in either 12-hour (AM/PM) or 24-hour format

• Also displays day of the week

• Time is adjustable via set mode (HH → MM → SS)

2. Calendar Mode

• Displays current day and date

• Month and day sequence may vary by market (MM-DD or DD-MM)

• Manual date correction required for months under 31 days

3. Multi-Alarm Mode

• Up to three daily alarms can be programmed

• Each alarm operates independently

• Alarms set using HH and MM

• Piezo buzzer provides audio notification

• Alarms can be toggled ON/OFF individually

4. Stopwatch Mode

• 1/10-second resolution

• Maximum duration: 59 minutes, 59.9 seconds

• Start, stop, and reset options using side buttons

Button Configuration (Typical)

Watches with the A354A module commonly feature four pushers:

• Button A (Top Left) – Cycle through modes (Time → Calendar → Alarm 1–3 → Stopwatch)

• Button B (Bottom Left) – Select digit for setting or toggle alarm ON/OFF

• Button C (Top Right) – Advance setting values or start/stop stopwatch

• Button D (Bottom Right) – Reset stopwatch or confirm alarm

Button layout may vary slightly depending on the watch model but generally follows this configuration.

Setting Instructions

To adjust time, calendar, or alarms:

1. Enter the appropriate mode via Button A

2. Press and hold Button B to enter setting mode

3. Use Button C to advance the value

4. Use Button B to move to the next field

5. Press Button A to save and exit the setting mode

Each alarm (AL1, AL2, AL3) is set independently using the same process.

Battery Replacement and AC Reset

An AC reset is required after installing a new battery.

Steps:

1. Open the case back using the correct tool

2. Remove the spent SR1120W battery with plastic tweezers

3. Insert a new battery, ensuring correct polarity

4. Locate the AC (All Clear) terminal on the circuit board (often labeled)

5. Short the AC contact to the battery’s negative terminal (case body or contact spring) using metal tweezers for 2–3 seconds

6. The LCD will flash all segments, then revert to the default time display

Skipping this reset may cause the display to remain blank or malfunction.

Maintenance Tips

• No lubrication needed – fully electronic module

• Buzzer contact can corrode over time—clean it if alarm is faint or silent

• Sticky or unresponsive buttons may be fixed with internal cleaning and contact restoration

• LCD fading is irreversible—requires donor module replacement

• Most watches using this module were not highly water-resistant

Watch Models and Use Cases

The Seiko A354A was used in multifunction digital watches, often sold under the “Multi-Alarm” or “Chronograph” labels. These watches included:

• Stainless steel or plated rectangular cases

• Alarm icons printed on bezels

• International models sold globally, especially in Asia and Europe

Reference numbers include A354-5000, A354-501A, and similar.

Conclusion

The Seiko A354A movement is a prime example of Seiko’s digital innovation in the early 1980s. Its support for multiple alarms, combined with stopwatch and calendar functions, made it a functional favorite for both casual users and professionals. Decades later, it remains a reliable and collectible module in Seiko’s vintage digital legacy.