Casio module 5451: user manual and setup (EFR-556D, EFR-556DB, EFR-556L)

The module number is engraved on the back of the Casio watch. It is a four-digit number and does not match the model name. If the case back says 5451, this manual is for your watch. The Casio guide is shared by modules 5434 and 5451, and the steps for 5451 are described here.

Which watches use module 5451

Module 5451 is analog with a crown and two buttons. The watch has an hour, minute and second hand. There is also a separate 24-hour hand and a day-of-month indicator. The stopwatch is read on its own second and minute hands. According to the manual, some models show part of the information with rotating discs instead of hands. In the Classic store this module is found in the following Edifice models:

• EFR-556L-1AVUEF – Casio Edifice EFR-556L-1AVUEF
• EFR-556DB-2AVUEF – Casio Edifice EFR-556DB-2AVUEF watch
• EFR-556D-1AVUEF – Casio Edifice EFR-556D-1AVUEF

Buttons and crown

The watch has two buttons, marked in the manual as A and B. Button A starts, stops and resumes the stopwatch. Button B takes a split time and resets the stopwatch. The crown has two pulled-out positions. The first click (Click 1) is used to change the day. The second click (Click 2) is used to set the time and to correct the stopwatch hands.

Some models water resistant to 100 or 200 meters have a screw-lock crown. Before using it, rotate it towards you to unscrew it. Then pull it out without excessive force. While the crown is unscrewed, the watch loses its water resistance. After setting, screw the crown back in fully.

How to set the time and date

Setting the time:

1. Wait for the second hand to reach 12 o'clock.
2. Pull the crown out to the second click (Click 2).
3. Rotate the crown to set the time.
4. Push the crown back in to the normal position.

Take care to set the correct morning or afternoon time. Use the 24-hour hand as a guide. When changing the time, move the minute hand four or five minutes past the desired position. Then move it back to the exact minute. While the crown is pulled out, the watch does not keep time.

Setting the day:

1. Pull the crown out to the first click (Click 1).
2. Rotate the crown to set the day of the month.
3. Push the crown back in.

The day indicator works with a 31-day month. For shorter months, correct it manually. Do not change the day between 9:00 PM and 1:00 AM. In this interval the indicator may not advance correctly at midnight.

Stopwatch

The stopwatch measures elapsed time in 1-second steps. The maximum range is 29 minutes and 59 seconds. Measurement stops automatically after 30 minutes. Do not operate the stopwatch while the crown is pulled out.

Elapsed time:

• A – start
• A – stop
• A – resume
• A – stop
• B – reset

Split time:

• A – start
• B – split (the hands stop)
• B – split release
• A – stop
• B – reset

Two finishes:

• A – start
• B – split when the first runner finishes; their time is shown
• A – stop when the second runner finishes
• B – split release; the time of the second runner is shown
• B – reset

Correcting the home positions of the hands

Do this if the stopwatch hands do not return to 12 o'clock after a reset.

1. Pull the crown out to the second click (Click 2).
2. Use button A (clockwise) and button B (counterclockwise) to move the stopwatch second and minute hands to 12 o'clock.
3. Holding down a button moves the second hand at high speed until you release it.
4. The stopwatch minute hand is synchronized with the second hand and moves together with it.
5. Push the crown back in.

While the crown is pulled out, the watch does not keep time. After the procedure, set the correct time again.

Rotating bezel

If the model has a rotating bezel, align the ▼ marker with the minute hand. The bezel then shows how much time has passed since the alignment.

Battery and accuracy

The watch runs on one SR920SW silver oxide battery. Its life is about 3 years with 30 minutes of stopwatch operation per day. Accuracy is on average ±20 seconds per month.

The original Casio manual (PDF)

Casio module 5451 manual (PDF, English) is the official Casio document for modules 5434 and 5451 with all diagrams of the hands and buttons.

Casio at Classic. Browse all Casio watches at Classic or the manuals for all Casio modules. There are two stores: Boutique CLASSIC on Knyaz Boris I 32 and Mall Varna.