Introduction to the Seiko 7F22A

The Seiko 7F22A is a high-accuracy quartz (HAQ) movement introduced in the early 1990s as part of Seiko's advanced 7F-series. It was one of the most sophisticated quartz calibers of its time, featuring a perpetual calendar, instant date change, and thermocompensation. Designed for durability and precision, the 7F22A was also engineered with no plastic parts, making it highly serviceable and reliable for long-term ownership.

This movement is most commonly found in Seiko Perpetual Calendar watches, with elegant designs targeted toward professionals who valued functionality, low maintenance, and to-the-second accuracy.

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Key Specifications

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Notable Features

Thermocompensation

The 7F22A uses a temperature-compensated quartz oscillator, which adjusts for environmental changes to maintain ±20 seconds per year accuracy. This is a major step above standard quartz movements (which typically drift ±15 seconds per month) and places the 7F22A in the High Accuracy Quartz (HAQ) category.

Perpetual Calendar

The calendar mechanism is programmed to account for:

• Leap years

• Short months

• 31-day cycles

This eliminates the need for manual correction until February 28, 2100, even across leap years. The calendar system is driven by a stepper motor that adjusts the date instantly at midnight.

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Functional Layout

Most watches using the 7F22A display:

• Hour, minute, and central seconds hands

• Date window (usually at 3 o’clock or 4:30)

• Some variants include a leap year indicator or four-digit year setting through case pushers

There are no subdials or digital screens. All perpetual calendar functions are fully mechanical and operated via the crown and pushers.

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Setting the Time and Calendar

Crown Positions:

1. Pushed in – Normal operation

2. First click – Set year, month, and day via case pushers (if equipped)

3. Second click – Set time (hacking seconds activated)

Setting Procedure Overview:

1. Pull crown to the first click.

2. Use recessed pushers (often at 2 or 4 o’clock) to cycle through year/month/day settings.

3. Set current year (last two digits), month, and day.

4. Pull the crown to the second click and rotate to set time.

5. Return crown to the normal position.

Note: Some models use crown-only input for full configuration. Refer to model-specific diagrams for precise method.

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Battery Replacement and Circuit Reset

Battery Type: SR927W
Battery Life: ~5 years

EOL (End-of-Life) Indicator: The seconds hand jumps every 2 seconds when the battery is low.

Replacement Procedure:

1. Open the case back carefully with a case knife or wrench.

2. Remove the old battery using non-metallic tweezers.

3. Insert a fresh SR927W cell.

4. Short the AC contact point to the battery’s positive terminal for 1–2 seconds using metal tweezers to reset the IC.

5. Calibrate the calendar if necessary.

Always reseal the case and inspect or replace the gasket to preserve water resistance.

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Servicing Notes

• Metal construction throughout (no plastic gears), making this a fully serviceable quartz movement.

• Calendar cam and lever system should be cleaned and lubricated during full service.

• 4 jewels support the rotor and geartrain, extending movement longevity.

• Stepper motor coils are robust, but avoid magnetic exposure.

It is recommended that full servicing be carried out every 8 to 10 years or when timekeeping or calendar behavior becomes erratic.

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Troubleshooting

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Final Thoughts

The Seiko 7F22A stands as one of the most technically refined quartz movements Seiko has ever produced. Its combination of:

• Perpetual calendar accuracy

• Long battery life

• High-performance thermocompensation

• Full metal geartrain with jeweled bearings

• Instant date change mechanism

…makes it a serious tool for users who demand accuracy and reliability without daily interaction.

Though no longer in production, watches powered by the 7F22A remain highly collectible, and when properly maintained, can continue functioning with precision for decades.

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