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This is a genuine ETA 7750-2577 day jumper, an original Swiss-made component for the ETA/Valjoux 7750 automatic chronograph movement. As a critical part of the day-date mechanism, the day jumper works in conjunction with the day driving wheel and day star to advance the day display at midnight .
This brand new original part is essential for watchmakers restoring proper day-date function when the original jumper becomes worn or damaged.
Genuine ETA Part – Swiss factory-original, perfect fit for 7750 movements.
Key Day Mechanism Component – Responsible for advancing the day disc at midnight for accurate calendar display.
Precision Machined – Accurate spring arm and pawl shape for consistent jumping torque.
Essential for Service – Replace when day jumping fails (no jump, half-jump, or weak jump).
Compatible Movements – Designed for ETA 7750 series (including 7750, 7751, 7753, etc.).
| Parameter | Details |
|---|---|
| Part Name | Day Jumper |
| Part Number | ETA 7750-2577 |
| Compatible Movements | ETA/Valjoux 7750 automatic chronograph and variants |
| Function | Advances the day display at midnight |
| Origin | Switzerland |
| Condition | Brand new, genuine |
ETA 7750 (Valjoux 7750) automatic chronograph (found in Breitling, Omega, IWC, etc.)
Variants: 7751 (full calendar moonphase), 7753 (tri-compax chronograph)
Repair of day display faults: no jump, half-jump, incorrect jump timing, or weak jump
Replacement of worn or broken day jumpers during movement service
1. Is this a genuine ETA day jumper?
Yes. It is a Swiss ETA factory-original part (7750-2577) for 7750 series movements.
2. What are the symptoms of a damaged day jumper?
Symptoms: date changes normally but day does not; day jumps halfway or gets stuck between two days; day jumps at the wrong time (e.g., not at midnight).
3. What should I pay attention to during installation?
Clean the day mechanism. Align the jumper with the day star’s teeth. The spring arm must sit correctly in its groove. Follow the ETA technical guide. Professional installation is strongly recommended.
4. Does the day star need to be replaced at the same time?
Not always. If the day star’s teeth are also worn, replace both. Try replacing the jumper first; if issues persist, replace the star.
5. Does this part fit the Sellita SW500?
SW500 is an alternative to 7750. The day mechanism parts are often interchangeable, but using dedicated SW500 parts is recommended for best fit. This genuine ETA part may work, but compatibility is not guaranteed.
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