ecostar-tv-power-supply-repair

ecostar-tv-power-supply-repair

I received a 40-inch EcoStar TV at my workshop that was not powering on. After opening the back cover and inspecting the main board (PCB), I noticed significant corrosion on the PCB, especially around the power supply section. The TV had been exposed to a humid environment, which likely accelerated the corrosion process. The 12V power supply would briefly appear and then disappear almost immediately, which indicated instability in the power delivery.

The power supply section contained an OB5269CP IC, a key component responsible for managing power regulation. When I checked the voltage at its VCC pin, it was fluctuating and blinking, confirming a problem in the supply circuit.

Initial Findings

During my initial inspection, I also observed an electrolytic capacitor (47uF/50V) near the IC, which was slightly swollen. Swollen capacitors are a common symptom of failure, as they lose their ability to store and regulate charge over time. I replaced the capacitor with a new one, but the issue persisted.

To further diagnose the problem, I performed a thorough inspection of the PCB and discovered that the 12V rectifier pins were severely corroded due to rust. Corrosion on the pins interrupts the flow of current, which can cause voltage drops or complete loss of power.

Fault Diagnosis

To address the corrosion issue, I first cleaned the affected area. I carefully scraped the PCB around the rectifier pins using a fine tool to remove the corroded material. I also ensured that the copper traces were intact and not damaged beyond repair. Once the corrosion was removed, I re-soldered the rectifier pins to ensure a solid electrical connection.

After completing the cleaning and re-soldering process, I powered the TV back on for testing. This time, the 12V power supply was stable and functioning perfectly. The TV powered on without any further issues, confirming that the corrosion had been the root cause of the problem.

Cause of the Fault

The root cause of the issue was corrosion due to prolonged exposure to moisture. Moisture causes a chemical reaction with the exposed copper traces of the PCB, leading to oxidation and rust formation. Over time, this corrosion weakens the electrical connections and disrupts the normal functioning of components. The areas where the copper was exposed without protective coating were particularly affected.

This phenomenon, known as Corrosion Attack, is a common issue in electronic devices exposed to humid or damp environments. It can severely damage electronic components, connections, and even render devices non-functional if not addressed in time.

Prevention Measures

To prevent such issues in the future, it is essential to:

Keep electronic devices in a dry and moisture-free environment.

Regularly clean and inspect devices, especially in areas with high humidity.

Apply protective coatings (like conformal coating) on PCBs to shield them from moisture and corrosion.

Address swollen or damaged capacitors immediately, as they can exacerbate power issues.

Highlighted Fault Area

The fault area has been clearly marked in the provided photo for your convenience. Kindly examine the image to identify the specific section where the problem exists.

Conclusion

In cases like this, thorough cleaning and inspection of the PCB, especially around corroded areas, are crucial for identifying and fixing power-related issues. Proper re-soldering of affected components can restore the flow of current and ensure stable power delivery. After carefully repairing the affected parts, the TV was restored to full functionality and tested for reliable operation.

This case highlights the importance of preventive measures and proper maintenance to extend the life of electronic devices and avoid costly repairs.

ecostar-tv-power-supply-repair
Highlighted Fault Area

facebook page

klv-48r472b-backlight-blink-repair

Youtube Channel

sony-klv-40W652D-sound-is-muted

 

 

 

 

 

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top