Ronda Caliber 505/515 Coil Block

Quantity	Discount (%)	Price
1 - 4	—	$3.00
5 - 14	5 %	$2.85
15+	10 %	$2.70

Quantity

Discount (%)

Price

1 - 4

—

$3.00

5 - 14

5 %

$2.85

15+

10 %

$2.70

Product Description

This is a genuine OEM Ronda coil block designed for the 505 and 515 quartz movements. It acts as the electromagnetic core of the stepper motor, converting electrical pulses from the circuit board into precise magnetic force to drive the gear train and hands. This new-old-stock (NOS) component is directly interchangeable, offering a straightforward solution to restore movement function without replacing the entire caliber. It is also compatible with Ronda calibers 507, 513 and 517.

Features & Function

Genuine Ronda Part – OEM quality, not a copy, ensures perfect fit and reliability.

Stepper Motor Core – Converts electrical pulses to magnetic force to drive the rotor and gear train.

Direct Replacement – Same interface and mounting holes as the original; no modification needed.

Wide Compatibility – Also fits Ronda calibers 507, 513, 517.

Cost‑Effective Repair – Replacing a faulty coil costs less than replacing the whole movement.

Specifications

Parameter	Details
Compatible Calibers	Ronda 505, 515 (also 507, 513, 517)
Type	Genuine OEM (new old stock)
Function	Stepper motor coil
Main Role	Converts electrical pulses to magnetic force for timekeeping
Installation	Direct replacement of original coil

Applications

Ronda 505 quartz movements (typically three‑hand or two‑hand with date)
Ronda 515 quartz movements (similar functionality)
Compatible with Ronda 507, 513, 517 calibers
For movements that have stopped due to open circuit, short circuit, moisture corrosion, or physical damage to the coil
Ideal for watchmakers during service or repair for quick replacement

Frequently Asked Questions

1. Is this a genuine Ronda coil?
Yes. It is an original OEM new‑old‑stock part, not a third‑party copy.

2. How can I tell if the coil needs replacement?
Typical symptoms: the movement does not run with a fresh battery. Measure coil resistance with a multimeter – normal range is several hundred to two thousand ohms. An infinite reading (open) or significant deviation indicates a bad coil.

3. What should I pay attention to during installation?
Disconnect the battery first. Align the coil with the locating pins, ensuring good contact with the circuit board. Use non‑magnetic tweezers and avoid static. The rotor should spin freely after installation. Professional help is recommended.

4. Is this coil compatible with all 515 sub‑variants?
The Ronda 515 family (e.g., 515.111, 515.222) typically shares the same coil module. The 505 and 515 coils are identical, and compatibility extends to 507, 513, 517 as well. Compare the appearance with your original if unsure.

5. Does replacing the coil require re‑calibration?
No. Timekeeping accuracy is determined by the quartz crystal on the circuit board. Replacing the coil does not affect frequency; just confirm the second hand moves smoothly. A timing machine check is optional.