--- description: Genuine MIYOTA JS25 coil block (Long) for JS25 meca-quartz chronograph. Japanese-made electronic component. Professional watch repair. title: MIYOTA/CITIZEN JS25 Coil Block(Long) - Sofly image: https://www.soflypart.com/wp-content/uploads/2019/05/JS25COLONG.jpg --- [Skip to content](#content) * [ Home ](https://www.soflypart.com "Home") * [Products](https://www.soflypart.com/shop/ "Products") * [Watch Circuit & Coil](https://www.soflypart.com/product-category/watch-parts/circuit-and-coil/ "Watch Circuit & Coil") * [Watch Parts](https://www.soflypart.com/product-category/watch-parts/ "Watch Parts") * **MIYOTA/CITIZEN JS25 Coil Block(Long)** [![MIYOTA/CITIZEN JS25 Coil Block(Long)](https://www.soflypart.com/wp-content/uploads/2019/05/JS25COLONG.jpg.webp)](https://www.soflypart.com/wp-content/uploads/2019/05/JS25COLONG.jpg) [![MIYOTA/CITIZEN JS25 Coil Block(Long) - Image 2](https://www.soflypart.com/wp-content/uploads/2019/05/JS25COLONGB.jpg.webp)](https://www.soflypart.com/wp-content/uploads/2019/05/JS25COLONGB.jpg) # MIYOTA/CITIZEN JS25 Coil Block(Long) $2.50 You Saved | Brand | Choose an optionMIYOTA![MIYOTA](https://www.soflypart.com/wp-content/uploads/2023/07/36.jpg)[Clear](#) | | ----- | ------------------------------------------------------------------------------------------------------ | ### Discount | Quantity | Discount (%) | Price | | -------- | ------------ | ----- | | 1 - 4 | — | $2.50 | | 5 - 9 | 5 % | $2.38 | | 10+ | 10 % | $2.25 | ### Discount | Quantity | Discount (%) | Price | | -------- | ------------ | ----- | | 1 - 4 | — | $2.50 | | 5 - 9 | 5 % | $2.38 | | 10+ | 10 % | $2.25 | MIYOTA/CITIZEN JS25 Coil Block(Long) quantity Add to cart x [ Checkout ](https://www.soflypart.com/checkout/) * repair Covers 99% of Repair Needs * Wholesale Discounts * Fast Global Shipping * 24/7 Customer Support ## Product Description This is a **genuine MIYOTA/CITIZEN JS25 coil block (Long)**, an original Japanese-made electronic component for the JS25 meca-quartz chronograph movement. The coil block is the core of the movement‘s motor system, generating the precise electromagnetic impulses that drive the stepper motor to power the timekeeping and chronograph functions . This brand new original part is essential for watchmakers restoring proper movement function when the original coil becomes damaged or fails. ## Key Features & Functions * Genuine MIYOTA/CITIZEN original part * Designed for JS25 meca-quartz chronograph movement * Generates electromagnetic impulses for stepper motor * Core electronic component of the movement * Made in Japan * Brand new, factory-fresh condition **About the JS25 Movement** The MIYOTA JS25 is a meca-quartz chronograph movement that combines quartz timekeeping with a mechanical chronograph module . Key specifications include : | Specification | Details | | ------------- | -------------------------------------------------- | | Caliber | JS25 | | Size | 12 1/2‴ | | Thickness | 4.30 mm | | Accuracy | ±20 seconds/month | | Battery life | 3 years | | Functions | Chronograph (30-minute/seconds), 24-hour, calendar | ## Usage Instructions **Signs of Coil Block Failure:** * Watch runs intermittently or stops completely with a fresh battery * Seconds hand jumps erratically (e.g., 2-second or 4-second jumps) * Chronograph functions do not operate correctly * Watch does not run at all despite a new battery * Visible damage to the coil (broken wire, discoloration) **Important Pre-Installation Note:** Before replacing the coil block, always install a **fresh, high-quality battery**. Even new batteries can have voltage drop, and a weak battery can mimic coil failure symptoms. ## Installation Instructions **Tools Required:** * Non-metallic tweezers * Small screwdriver (for movement disassembly) * Movement holder * Loupe or magnification * Fresh battery (for testing) **Step-by-Step Installation:** **Step 1: Movement Preparation** * Remove the movement from the watch case * Remove the battery * Remove the hands and dial (if accessing from dial side) **Step 2: Remove the Old Coil Block** * Locate the coil block on the main plate (typically near the stepper motor) * Carefully desolder or detach the coil connections (if applicable) * Remove the retaining screws and lift out the old coil block * Note the orientation for reinstallation **Step 3: Clean the Contacts** * Clean the contact pads on the circuit board using isopropyl alcohol * Ensure no old solder or debris remains **Step 4: Install the New Coil Block** * Position the new genuine MIYOTA JS25 coil block onto the movement plate * Ensure all contact pins align correctly with the circuit board terminals * Secure with the retaining screws **Step 5: Soldering (if required)** * If the coil requires soldering, use a fine-point soldering iron with minimal heat * Solder the coil wires to the circuit board pads **Step 6: Testing** * Install a fresh battery * Verify that the seconds hand advances in one-second increments * Test chronograph functions (start, stop, reset) * Test all functions before reassembly **Important Notes:** * The coil block is sensitive to electrostatic discharge (ESD) – work on an ESD-safe surface * The JS25 has a thickness of 4.30mm – handle the movement carefully during reassembly * Professional installation is recommended for those without movement service experience ## Repair Guide **Common Symptoms of Coil Failure:** | Symptom | Possible Cause | | ---------------------------------------------- | ------------------------------------------------- | | Watch does not run with new battery | Open circuit in coil winding | | Seconds hand jumps in 2 or 4-second increments | Low battery or failing coil (battery check first) | | Chronograph does not operate | Damaged coil or poor connection | | Watch runs intermittently | Damaged coil or poor connection | | Visible wire breakage or discoloration | Physical damage or overheating | **Diagnostic Process:** 1. **Battery Test**: Install a fresh, high-quality battery. Even new batteries can have voltage drop. 2. **Visual Inspection**: Under magnification, examine the coil for broken wires, burn marks, or discoloration. 3. **Continuity Test**: Using a multimeter, check for continuity across the coil terminals. 4. **Function Test**: If the coil passes visual inspection but the watch still fails, the circuit board or stepper motor may be at fault. **When Replacement is Necessary:** * Visible wire breakage or damage to the coil * Burn marks or discoloration indicating electrical failure * No continuity across coil terminals * Previous attempts to clean or repair have failed **Preventive Maintenance:** * Use high-quality batteries to prevent leakage * Avoid exposing the movement to moisture * Replace batteries every 2-3 years to prevent corrosion * Store watches in a dry environment **When to Seek Professional Help:** * You lack experience with ESD-safe handling * Soldering is required and you are not trained in micro-soldering * The circuit board or stepper motor shows signs of damage * You do not have proper testing equipment ## Frequently Asked Questions **Q1: What causes a coil to fail?** **A:** Common causes include battery leakage (corrosion damaging the fine coil wire), physical impact, moisture ingress, or electrical overload. Over time, the extremely fine copper wire in the coil can also develop an open circuit due to metal fatigue or manufacturing defects. **Q2: Can I install this coil block myself?** **A:** If you have experience with movement disassembly and proper ESD-safe handling, installation is possible. However, this repair may require soldering, which demands steady hands and appropriate equipment. Professional installation is recommended for most users. **Q3: What is the accuracy of the JS25 movement?** **A:** The JS25 movement has an accuracy rating of **±20 seconds per month** at room temperature . ## Why Choose SOFLY Watch Parts? * Fast worldwide shipping within 3 business days. * Competitive pricing on Seiko/Hattori calibers. * 3,000+ watch movements and parts in stock. * Trusted by watchmakers worldwide. * Personalized sourcing support via **info@soflypart.com** or WhatsApp **+86 18620212114**. ##### Our Popular Items [ ![Zenith El Primero 18.0240.4021 Crystal](https://www.soflypart.com/wp-content/uploads/2022/07/DSC09824.jpg) ](https://www.soflypart.com/product/generic-zenith-el-primero-chronomaster-02-0310-400-sapphire-crystal-29-85mm/) ### [Generic Zenith El Primero Chronomaster 02.0310.400 Sapphire Crystal 29.85mm ](https://www.soflypart.com/product/generic-zenith-el-primero-chronomaster-02-0310-400-sapphire-crystal-29-85mm/) [ ![Breguet Classique 8067 Sapphire 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Japanese-made electronic component. Professional watch repair.","sku":"1103056","category":"Watch Parts > Watch Circuit & Coil","mainEntityOfPage":{"@id":"https://www.soflypart.com/product/miyota-citizen-js25-movement-coil-blocklong/#webpage"},"image":[{"@type":"ImageObject","url":"https://www.soflypart.com/wp-content/uploads/2019/05/JS25COLONG.jpg","height":"580","width":"580"},{"@type":"ImageObject","url":"https://www.soflypart.com/wp-content/uploads/2019/05/JS25COLONGB.jpg","height":"580","width":"580"}],"url":"https://www.soflypart.com/product/miyota-citizen-js25-movement-coil-blocklong/","productGroupID":"1103056","hasVariant":[{"@type":"Product","sku":"1103056","name":"MIYOTA/CITIZEN JS25 Coil Block(Long) - MIYOTA","description":"Product Description This is a\u00a0genuine MIYOTA/CITIZEN JS25 coil block (Long), an original Japanese-made electronic component for the JS25 meca-quartz chronograph movement. The coil block is the core of the movement\u2018s motor system, generating the precise electromagnetic impulses that drive the stepper motor to power the timekeeping and chronograph functions . This brand new original part is essential for watchmakers restoring proper movement function when the original coil becomes damaged or fails. Key Features & Functions Genuine MIYOTA/CITIZEN original part Designed for JS25 meca-quartz chronograph movement Generates electromagnetic impulses for stepper motor Core electronic component of the movement Made in Japan Brand new, factory-fresh condition About the JS25 Movement The MIYOTA JS25 is a meca-quartz chronograph movement that combines quartz timekeeping with a mechanical chronograph module . Key specifications include : Specification Details Caliber JS25 Size 12 1/2\u2034 Thickness 4.30 mm Accuracy \u00b120 seconds/month Battery life 3 years Functions Chronograph (30-minute/seconds), 24-hour, calendar Usage Instructions Signs of Coil Block Failure: Watch runs intermittently or stops completely with a fresh battery Seconds hand jumps erratically (e.g., 2-second or 4-second jumps) Chronograph functions do not operate correctly Watch does not run at all despite a new battery Visible damage to the coil (broken wire, discoloration) Important Pre-Installation Note: Before replacing the coil block, always install a\u00a0fresh, high-quality battery. Even new batteries can have voltage drop, and a weak battery can mimic coil failure symptoms. Installation Instructions Tools Required: Non-metallic tweezers Small screwdriver (for movement disassembly) Movement holder Loupe or magnification Fresh battery (for testing) Step-by-Step Installation: Step 1: Movement Preparation Remove the movement from the watch case Remove the battery Remove the hands and dial (if accessing from dial side) Step 2: Remove the Old Coil Block Locate the coil block on the main plate (typically near the stepper motor) Carefully desolder or detach the coil connections (if applicable) Remove the retaining screws and lift out the old coil block Note the orientation for reinstallation Step 3: Clean the Contacts Clean the contact pads on the circuit board using isopropyl alcohol Ensure no old solder or debris remains Step 4: Install the New Coil Block Position the new genuine MIYOTA JS25 coil block onto the movement plate Ensure all contact pins align correctly with the circuit board terminals Secure with the retaining screws Step 5: Soldering (if required) If the coil requires soldering, use a fine-point soldering iron with minimal heat Solder the coil wires to the circuit board pads Step 6: Testing Install a fresh battery Verify that the seconds hand advances in one-second increments Test chronograph functions (start, stop, reset) Test all functions before reassembly Important Notes: The coil block is sensitive to electrostatic discharge (ESD) \u2013 work on an ESD-safe surface The JS25 has a thickness of 4.30mm\u00a0\u00a0\u2013 handle the movement carefully during reassembly Professional installation is recommended for those without movement service experience Repair Guide Common Symptoms of Coil Failure: Symptom Possible Cause Watch does not run with new battery Open circuit in coil winding Seconds hand jumps in 2 or 4-second increments Low battery or failing coil (battery check first) Chronograph does not operate Damaged coil or poor connection Watch runs intermittently Damaged coil or poor connection Visible wire breakage or discoloration Physical damage or overheating Diagnostic Process: Battery Test: Install a fresh, high-quality battery. Even new batteries can have voltage drop. Visual Inspection: Under magnification, examine the coil for broken wires, burn marks, or discoloration. Continuity Test: Using a multimeter, check for continuity across the coil terminals. Function Test: If the coil passes visual inspection but the watch still fails, the circuit board or stepper motor may be at fault. When Replacement is Necessary: Visible wire breakage or damage to the coil Burn marks or discoloration indicating electrical failure No continuity across coil terminals Previous attempts to clean or repair have failed Preventive Maintenance: Use high-quality batteries to prevent leakage Avoid exposing the movement to moisture Replace batteries every 2-3 years to prevent corrosion Store watches in a dry environment When to Seek Professional Help: You lack experience with ESD-safe handling Soldering is required and you are not trained in micro-soldering The circuit board or stepper motor shows signs of damage You do not have proper testing equipment Frequently Asked Questions Q1: What causes a coil to fail? A:\u00a0Common causes include battery leakage (corrosion damaging the fine coil wire), physical impact, moisture ingress, or electrical overload. Over time, the extremely fine copper wire in the coil can also develop an open circuit due to metal fatigue or manufacturing defects. Q2: Can I install this coil block myself? A:\u00a0If you have experience with movement disassembly and proper ESD-safe handling, installation is possible. However, this repair may require soldering, which demands steady hands and appropriate equipment. Professional installation is recommended for most users. Q3: What is the accuracy of the JS25 movement? A:\u00a0The JS25 movement has an accuracy rating of\u00a0\u00b120 seconds per month\u00a0at room temperature\u00a0. Why Choose SOFLY Watch Parts? Fast worldwide shipping within 3 business days. Competitive pricing on Seiko/Hattori calibers. 3,000+ watch movements and parts in stock. Trusted by watchmakers worldwide. Personalized sourcing support via\u00a0info@soflypart.com\u00a0or WhatsApp\u00a0+86 18620212114.","image":"https://www.soflypart.com/wp-content/uploads/2019/05/JS25COLONG-150x150.jpg","offers":{"@type":"Offer","description":"Product Description This is a\u00a0genuine MIYOTA/CITIZEN JS25 coil block (Long), an original Japanese-made electronic component for the JS25 meca-quartz chronograph movement. The coil block is the core of the movement\u2018s motor system, generating the precise electromagnetic impulses that drive the stepper motor to power the timekeeping and chronograph functions . This brand new original part is essential for watchmakers restoring proper movement function when the original coil becomes damaged or fails. Key Features & Functions Genuine MIYOTA/CITIZEN original part Designed for JS25 meca-quartz chronograph movement Generates electromagnetic impulses for stepper motor Core electronic component of the movement Made in Japan Brand new, factory-fresh condition About the JS25 Movement The MIYOTA JS25 is a meca-quartz chronograph movement that combines quartz timekeeping with a mechanical chronograph module . Key specifications include : Specification Details Caliber JS25 Size 12 1/2\u2034 Thickness 4.30 mm Accuracy \u00b120 seconds/month Battery life 3 years Functions Chronograph (30-minute/seconds), 24-hour, calendar Usage Instructions Signs of Coil Block Failure: Watch runs intermittently or stops completely with a fresh battery Seconds hand jumps erratically (e.g., 2-second or 4-second jumps) Chronograph functions do not operate correctly Watch does not run at all despite a new battery Visible damage to the coil (broken wire, discoloration) Important Pre-Installation Note: Before replacing the coil block, always install a\u00a0fresh, high-quality battery. Even new batteries can have voltage drop, and a weak battery can mimic coil failure symptoms. Installation Instructions Tools Required: Non-metallic tweezers Small screwdriver (for movement disassembly) Movement holder Loupe or magnification Fresh battery (for testing) Step-by-Step Installation: Step 1: Movement Preparation Remove the movement from the watch case Remove the battery Remove the hands and dial (if accessing from dial side) Step 2: Remove the Old Coil Block Locate the coil block on the main plate (typically near the stepper motor) Carefully desolder or detach the coil connections (if applicable) Remove the retaining screws and lift out the old coil block Note the orientation for reinstallation Step 3: Clean the Contacts Clean the contact pads on the circuit board using isopropyl alcohol Ensure no old solder or debris remains Step 4: Install the New Coil Block Position the new genuine MIYOTA JS25 coil block onto the movement plate Ensure all contact pins align correctly with the circuit board terminals Secure with the retaining screws Step 5: Soldering (if required) If the coil requires soldering, use a fine-point soldering iron with minimal heat Solder the coil wires to the circuit board pads Step 6: Testing Install a fresh battery Verify that the seconds hand advances in one-second increments Test chronograph functions (start, stop, reset) Test all functions before reassembly Important Notes: The coil block is sensitive to electrostatic discharge (ESD) \u2013 work on an ESD-safe surface The JS25 has a thickness of 4.30mm\u00a0\u00a0\u2013 handle the movement carefully during reassembly Professional installation is recommended for those without movement service experience Repair Guide Common Symptoms of Coil Failure: Symptom Possible Cause Watch does not run with new battery Open circuit in coil winding Seconds hand jumps in 2 or 4-second increments Low battery or failing coil (battery check first) Chronograph does not operate Damaged coil or poor connection Watch runs intermittently Damaged coil or poor connection Visible wire breakage or discoloration Physical damage or overheating Diagnostic Process: Battery Test: Install a fresh, high-quality battery. Even new batteries can have voltage drop. Visual Inspection: Under magnification, examine the coil for broken wires, burn marks, or discoloration. Continuity Test: Using a multimeter, check for continuity across the coil terminals. Function Test: If the coil passes visual inspection but the watch still fails, the circuit board or stepper motor may be at fault. When Replacement is Necessary: Visible wire breakage or damage to the coil Burn marks or discoloration indicating electrical failure No continuity across coil terminals Previous attempts to clean or repair have failed Preventive Maintenance: Use high-quality batteries to prevent leakage Avoid exposing the movement to moisture Replace batteries every 2-3 years to prevent corrosion Store watches in a dry environment When to Seek Professional Help: You lack experience with ESD-safe handling Soldering is required and you are not trained in micro-soldering The circuit board or stepper motor shows signs of damage You do not have proper testing equipment Frequently Asked Questions Q1: What causes a coil to fail? A:\u00a0Common causes include battery leakage (corrosion damaging the fine coil wire), physical impact, moisture ingress, or electrical overload. Over time, the extremely fine copper wire in the coil can also develop an open circuit due to metal fatigue or manufacturing defects. Q2: Can I install this coil block myself? A:\u00a0If you have experience with movement disassembly and proper ESD-safe handling, installation is possible. However, this repair may require soldering, which demands steady hands and appropriate equipment. Professional installation is recommended for most users. Q3: What is the accuracy of the JS25 movement? A:\u00a0The JS25 movement has an accuracy rating of\u00a0\u00b120 seconds per month\u00a0at room temperature\u00a0. Why Choose SOFLY Watch Parts? Fast worldwide shipping within 3 business days. Competitive pricing on Seiko/Hattori calibers. 3,000+ watch movements and parts in stock. Trusted by watchmakers worldwide. Personalized sourcing support via\u00a0info@soflypart.com\u00a0or WhatsApp\u00a0+86 18620212114.","price":"2.5","priceCurrency":"USD","availability":"http://schema.org/InStock","itemCondition":"NewCondition","priceValidUntil":"2027-12-31","url":"https://www.soflypart.com/product/miyota-citizen-js25-movement-coil-blocklong/?attribute_pa_brand=miyota"}}],"@id":"https://www.soflypart.com/product/miyota-citizen-js25-movement-coil-blocklong/#richSnippet"}]} ```