1. Introduction and Overview
This manual provides comprehensive instructions for the Hanhart Stopwatch Model 121-1515-00. This precision instrument is a hand-wound mechanical stopwatch designed for accurate time measurement in various professional and personal applications. It features a 1/5 second measurement scale and a 30-minute timer with a 60-second revolution.
Key features include:
- 1/5 second measurement with a 1/5 second scale.
- Hand-wound mechanical movement.
- 30-minute timer with a 60-second revolution.
- Convenient for darkroom work due to luminous properties.
- Provides 3-4 hours of visibility after 1 hour of fluorescent light exposure.
- Equipped with daily life water resistance.

Figure 1: Hanhart Stopwatch Model 121-1515-00. This image displays the front view of the stopwatch, showing its dial, hands, and crown/push-buttons.
2. Setup
The Hanhart Stopwatch Model 121-1515-00 is a hand-wound device. Before initial use or if the stopwatch has stopped, it requires winding.
- Winding the Movement: Gently turn the crown (usually located at the top or side) clockwise until you feel resistance. Do not overwind, as this can damage the mechanism. A full wind typically provides sufficient power for extended operation.
- Initial Reset: Ensure the stopwatch hands are at the zero position. If not, press the reset button (often integrated with the crown or a separate button) to return the hands to zero.
3. Operating Instructions
This stopwatch operates with a simple push-button mechanism for start, stop, and reset functions.
- Starting the Stopwatch: Press the top push-button (often the crown itself) firmly once to start the timing. The large second hand will begin to move.
- Stopping the Stopwatch: To stop the timing, press the same top push-button firmly once again. The hands will hold their position, indicating the elapsed time.
- Reading the Time:
- The large central hand measures seconds and 1/5 seconds. Each full revolution represents 60 seconds.
- The small sub-dial (if present, typically at the 12 o'clock position) measures elapsed minutes, up to 30 minutes.
- Read the precise time by noting the position of the large second hand against the 1/5 second scale and the minute hand on the sub-dial.
- Resetting the Stopwatch: After stopping, press the top push-button a third time (or a dedicated reset button, if separate) to return all hands to the zero position, preparing the stopwatch for a new measurement.
Note: For models with a side push-button, the sequence might be: Top button for Start/Stop, Side button for Reset. Refer to the specific design of your stopwatch.
4. Maintenance
Proper care and maintenance will ensure the longevity and accuracy of your Hanhart Stopwatch.
- Cleaning: Wipe the stopwatch regularly with a soft, dry cloth to remove dust and fingerprints. For stubborn marks, a slightly damp cloth can be used, followed immediately by a dry cloth. Avoid abrasive cleaners or solvents.
- Water Resistance: This stopwatch features daily life water resistance. This means it is protected against splashes, rain, and brief immersion. It is not suitable for swimming, showering, or diving. Do not operate the push-buttons while the stopwatch is wet.
- Luminous Display: The dial features luminous material for visibility in low-light conditions, particularly useful for darkroom work. To charge the luminosity, expose the stopwatch to a light source (natural or artificial) for approximately 1 hour. This will provide 3-4 hours of glow.
- Storage: Store the stopwatch in a dry, cool place, away from direct sunlight, extreme temperatures, and strong magnetic fields.
- Servicing: Mechanical stopwatches benefit from periodic professional servicing (e.g., cleaning and lubrication) every few years to maintain optimal performance. Contact an authorized Hanhart service center for such services.
5. Troubleshooting
If you encounter issues with your stopwatch, consider the following common solutions:
- Stopwatch not starting: Ensure the stopwatch is fully wound. If it is not wound, wind the crown clockwise until resistance is felt.
- Hands not resetting to zero: Press the reset button firmly. If the hands still do not align, there might be a mechanical issue requiring professional service.
- Inaccurate timing:
- Ensure the stopwatch is fully wound before use.
- Avoid exposing the stopwatch to strong magnetic fields, which can affect accuracy.
- Extreme temperature fluctuations can also impact performance.
- If accuracy issues persist, professional calibration or repair may be necessary.
- Water ingress: If water enters the stopwatch, immediately cease use and seek professional service to prevent further damage.
For issues not covered here, please contact Hanhart customer support or an authorized service center.
6. Specifications
| Feature | Detail |
|---|---|
| Brand | Hanhart |
| Model Number | 121-1515-00 |
| Measurement Unit | 1/5 second |
| Timer Capacity | 30 minutes (60-second revolution) |
| Movement Type | Hand-wound mechanical |
| Water Resistance | Daily life water resistant |
| Luminous Feature | Yes (3-4 hours visibility after 1 hour exposure) |
| Item Weight | 100 g |
| Package Dimensions | 11 x 9.2 x 3.2 cm |
7. Warranty and Support
For detailed information regarding the product warranty, please refer to the warranty card included with your purchase or visit the official Hanhart website. Warranty terms and conditions may vary by region and purchase date.
If you require technical assistance, spare parts, or professional servicing, please contact Hanhart customer support. Contact information can typically be found on the manufacturer's website or in the packaging materials.
Hanhart Official Website: www.hanhart.com




