Seiko Calibers 4R35/4R36/4R37/4R38/4R39
Characteristics of Mechanical Watches
These mechanical watches are powered by a mainspring. If the watch has stopped, manually wind the mainspring by turning the crown approximately 20 times to start the watch.
Unlike quartz watches where accuracy is measured monthly or yearly, the accuracy of mechanical watches is indicated by daily variation (slowing/speeding per day). The accuracy of mechanical watches can change depending on usage conditions such as how often the watch is worn, ambient temperature, wrist movements, and the degree of mainspring winding.
Exposure to strong magnetic fields can temporarily affect the watch's timekeeping. If exposed to a strong magnetic field, some parts may become magnetized. In such cases, demagnetization is required. Please consult the store where the watch was purchased.
Part Names
The diagrams below illustrate the parts of the watch faces for different calibers.
Caliber 4R35 & 4R37
Components: Hour hand, Minute hand, Second hand, Date display.
Caliber 4R36
Components: Hour hand, Minute hand, Second hand, Day and Date displays.
Caliber 4R38 & 4R39
Components: Hour hand, Minute hand, Second hand, 24-hour hand. Caliber 4R39 also has a date display.
Crown Positions:
- a) Initial Position: Manual winding of the watch.
- b) Pulled to First Click: Setting the date (and day for 4R36). The second hand continues to move.
- c) Pulled to Second Click: Setting the time. The second hand stops.
Usage
These watches feature both automatic and manual winding functions. When worn on the wrist, the mainspring is automatically wound by the movement of the arm. If the watch has stopped, it is recommended to wind it manually by turning the crown.
Manual Winding of the Mainspring using the Crown
- Slowly rotate the crown clockwise (towards the 12 o'clock position). Rotating the crown counter-clockwise (towards the 6 o'clock position) does not wind the mainspring.
- Continue rotating the crown until the mainspring is fully wound. The second hand will start moving.
- Set the time and date before wearing the watch.
The winding method is the same for calibers 4R35, 4R36, 4R37, 4R38, and 4R39.
* If your watch has a screw-lock crown, it is screwed into the case for additional protection. Unscrew the crown by turning it counter-clockwise before setting. After setting, screw the crown back in by turning it clockwise while applying light pressure. Do not force the crown if it feels tight; turn it counter-clockwise once and try again. Do not overtighten, as this may damage the threads.
How to Set Time and Date (for Calibers 4R35 and 4R37)
Ensure the watch is running before setting the time and date. The date is displayed on a sub-dial.
- Pull the crown out to the first click. (This does not affect the accuracy of the watch; the second hand continues to move).
- To set the date, rotate the crown counter-clockwise. Rotate until the previous day's date appears. For example, if today is the 5th, rotate counter-clockwise until '4' is displayed.
- Pull the crown out to the second click when the second hand is at the 12 o'clock position (it will stop). Rotate the crown until the date changes to the next day. The time is now set for AM. Continue moving the hands to set the current time.
- Return the crown to its initial position simultaneously with a time signal.
Warning: Do not set the date between 9:00 PM (21:00) and 1:00 AM. Doing so may cause the date to change incorrectly and lead to malfunction.
Caliber 4R37 is equipped with a 24-hour hand that moves in sync with the hour hand. When setting the time, ensure the 24-hour hand is set correctly.
Warning: The mechanism of a mechanical watch differs from that of a quartz watch. When correcting the time, set the minute hand slightly before the desired time, then move it to the exact mark.
How to Set Time, Day of the Week, and Date (for Caliber 4R36)
Before setting the day, date, and time, ensure the watch is running. The date and day are displayed on sub-dials. These indicators change every 24 hours; the date typically changes around midnight, and the day around 4 AM. If the AM/PM setting is incorrect, the date may change at noon and the day at 4:00 PM.
- Pull the crown out to the first click. (This does not affect the accuracy of the watch; the second hand continues to move).
- To set the day, rotate the crown clockwise.
- To set the date, rotate the crown counter-clockwise. Rotate until the previous day's date appears. For example, if today is the 5th, rotate counter-clockwise until '4' is displayed.
- Pull the crown out to the second click when the second hand is at the 12 o'clock position (it will stop). Rotate the crown until the date changes to the next day. The time is now set for AM. Continue moving the hands to set the current time.
- Return the crown to its initial position simultaneously with a time signal.
Warning: Do not set the date between 9:00 PM (21:00) and 4:00 AM. Doing so may cause the date to change incorrectly and lead to malfunction.
Warning: The mechanism of a mechanical watch differs from that of a quartz watch. When correcting the time, set the minute hand slightly before the desired time, then move it to the exact mark.
How to Set Time (for Calibers 4R38 and 4R39)
- Pull the crown out to the second click when the second hand is at the 12 o'clock position (it will stop).
- Rotate the crown to set the hour and minute hands to the current time.
- Return the crown to its initial position simultaneously with a time signal.
Caliber 4R39 is equipped with a 24-hour hand that moves in sync with the hour hand. When setting the time, ensure the 24-hour hand is set correctly.
Preserving Your Watch
Care for Your Watch
Under normal circumstances, your watch requires no special care and will function for many years. To ensure its longevity and prevent skin irritation, please wipe away moisture, sweat, or dirt with a soft, dry cloth immediately after removing the watch.
Leather Strap
Gently blot moisture from the strap using a soft, dry cloth. Do not rub the leather strap, as this may cause damage or color loss.
Metal Bracelet
To keep the bracelet clean, use a soft toothbrush moistened with clean water or mild soap. Be careful not to get water on the watch case.
Warning: Adjust the strap to allow a small gap between it and your wrist for ventilation. In some individuals, prolonged contact with the watch may cause irritation or allergic reactions. Possible causes of dermatitis include allergic reactions to metals or leather, or accumulated rust, dirt, or sweat on the watch or strap. If you experience any allergic symptoms or skin irritation, discontinue wearing the watch and consult a doctor.
Water Resistance
No Water Resistance: If the word “WATER RESISTANT” is not written on the case back, your watch has no water resistance. Be cautious to avoid getting it wet, as water can damage the watch mechanism. If the watch gets wet, we recommend taking it to the store where it was purchased or to a SEIKO SERVICE CENTER for inspection.
Water Resistance (3 Bar): If “WATER RESISTANT” is written on the case back, your watch is designed to withstand pressure up to 3 Bar and resist accidental contact with splashes or rain, but is not intended for swimming or diving.
Water Resistance (5 Bar): If “WATER RESISTANT 5 BAR” is written on the case back, your watch is designed to withstand pressure up to 5 Bar and can be used while swimming, sailing, or showering.
Water Resistance (10 Bar / 15 Bar / 20 Bar): If “WATER RESISTANT 10 BAR”, “WATER RESISTANT 15 BAR”, or “WATER RESISTANT 20 BAR” is written on the case back, your watch is designed to withstand pressure up to 10 (15, 20) Bar and can be used while bathing or shallow diving, but not for scuba diving. We recommend wearing SEIKO Diver's watches for scuba diving.
* Before using watches with 5, 10, 15, or 20 Bar water resistance in water, ensure the crown is fully pushed in. Do not operate the crown if the watch is wet or submerged. If the watch has been used in seawater, rinse it with fresh water and dry it completely.
When showering with a 5 Bar water-resistant watch, or bathing with a 10, 15, or 20 Bar water-resistant watch, please observe the following:
- Do not operate the crown when the watch is in soapy water or shampoo.
- Exposure to hot water may affect timekeeping accuracy. Accuracy will recover once the watch returns to normal temperature conditions.
Note: Bar pressure is a test pressure and should not be considered equivalent to actual diving depth, as swimming movements increase pressure at a given depth. Exercise caution when diving with your watch.
Precautions When Wearing Your Watch
- Be careful when holding an infant or small child while wearing the watch, as they may be injured or develop an allergic reaction from direct contact.
- Avoid impacts, drops, or scratches on hard surfaces, as well as strenuous sports activities, which may cause temporary malfunctions.
- There is a risk of injury when wearing the watch on your wrist, especially if you fall or collide with others or objects.
Where to Store Your Watch
- Do not leave your watch in places exposed to strong magnetic fields (e.g., near televisions, speakers, or magnetic bracelets) or static electricity.
- Do not leave your watch in places with strong vibrations.
- Do not leave your watch in dusty places.
- Do not expose your watch to chemicals or gases (e.g., organic solvents like gasoline and thinner, nail polish, aerosol sprays, detergents, glue, mercury, and iodine-based antiseptics).
- Avoid direct contact of your watch with hot water.
Periodic Checks
These watches are precise instruments with many moving parts lubricated with special oil. Insufficient lubrication or wear of parts can lead to inaccurate timekeeping or stoppage. Therefore, periodic checks are necessary.
Warranty and Repair Tips
For repairs or checks, please contact the store where the watch was purchased or a SEIKO SERVICE CENTER. For warranty service, please present your warranty certificate. Warranty terms are detailed in the warranty certificate; please read it carefully and keep it.
Troubleshooting
| Problem | Possible Causes | Possible Solutions |
|---|---|---|
| Watch stopped | Mainspring energy depleted | Wind the watch manually or shake it like a pendulum. If it does not run, contact the store for inspection. |
| Stops frequently despite daily wear | Worn for too short a period, or insufficient wrist movement. | Wear the watch for a longer period, or manually wind the mainspring when not wearing it. |
| Gains or loses time | Exposed to extreme temperatures for a long time. | Return the watch to normal temperature; accuracy should recover. |
| Gains or loses time | Left near a strong magnetic field for a long time. | Remove the watch from the magnetic field; accuracy should recover. If this does not help, contact the store where the watch was purchased. |
| Gains or loses time | Dropped, hit against a hard surface, or worn during strenuous sports. Subjected to strong vibrations. | Contact the store where the watch was purchased. |
| Date changes at 12 PM (AM/PM incorrect) | AM/PM setting is incorrect. | Advance the hour hand by 12 hours. |
| Condensation on the inside of the glass persists for a long time. | Moisture has entered the watch due to gasket damage. | Contact the store where the watch was purchased. |
| Watch not checked for over 3 years. | N/A | Contact the store where the watch was purchased. |
• In case of any other problems, please contact the store where the watch was purchased.
Accuracy of Mechanical Watches
The accuracy of mechanical watches is indicated by daily variation, approximately per week. The accuracy may deviate from the specified range due to slowing or speeding caused by usage conditions such as wearing duration, wrist movement, and mainspring winding. Key components in mechanical watches are made of metals that expand or contract with temperature, affecting accuracy. Mechanical watches may slow down at high temperatures and speed up at low temperatures. To maintain accuracy, it is important to regularly supply energy to the balance wheel that controls the escapement. The driving force of the mainspring, which powers the watch, is not uniform throughout its wind. A less wound mainspring provides less driving force. Consistent accuracy can be achieved by frequent wearing for automatic watches, and daily full winding at the same time for manual winding watches. Exposure to strong external magnetic fields can temporarily slow down or speed up the watch. Watch parts may become magnetized depending on the magnetic field strength. In such situations, consult the store where the watch was purchased, as the watch may require repair, including demagnetization.
Specifications
| # | Characteristic | Details |
|---|---|---|
| 1 | Calibers | 4R35: Three hands, dial (hour, minute, and second hands), date display. 4R36: Three hands, dial (hour, minute, and second hands), date and day displays. 4R37: Four hands, dial (hour, minute, second, and 24-hour hands), date display. 4R38: Three hands, dial (hour, minute, and second hands). 4R39: Four hands, dial (hour, minute, second, and 24-hour hands). |
| 2 | Vibrations per hour | 21,600 |
| 3 | Operating temperature range | Between -10 °C and 60 °C (Between 14 °F and 140 °F) |
| 4 | Power reserve per full wind | Slightly over 41 hours |
| 5 | Drive type | Automatic, with manual winding capability |
| 6 | Jewels | 4R35: 23 jewels 4R36, 4R37, 4R38, and 4R39: 24 jewels |
| 7 | Magnetic resistance | 4800 A/m (60 Gauss) |
• Specifications are subject to change for product improvement without prior notice.
